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Full text of "Your Computer Magazine (March 1983)"

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BRITAIN'S BJGGEST-SELLING HOME COMPUTER MAGAZINE ^*^^lTno..3 



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fl6kor4£ik) 
ZX SPECTRUM 



VIC 20 (ANY (\ABAO^r 




From our team of outstar''' 

come games crammec| 

HI-RESOLUT^EpS'HICS 
SENSATION^HyiTo EFFECTS 
FAST LOADirJMPCHINE CODE THRILLS 
SPECIAL SKILL LEVELS arar 

Hall OF FAME 




fniSSILE F1TTF19&J 

THE ULTIMATE EXPLOSIVE CHALLEWGE 



fig 

MONSTER m 
MUNCHER 

Ghosts energizers 
and a secret escape 




^ ^^^1^ 



Any Game Just 

INCLUDES V.A.T. AND Jst CLASS POST AND PACKING 



action 

£5.50 





ANY FAULT, YOUR GAME 
WILL BE REPLACED 
COMPLETELY FREE 



SPECTRUM GAMES 
FREEPOST Manchester M3 8BB 

SAME DAY CREDIT CARD SALFS 
06 1 -832 9 1 43 (74 hours) 

DEALER ENQUIRIES INVITED 



POST COUPON NOW TO ■■■■■■■■■! 

SPECTRUM GAMES 

FREEPOST A/IAIMCHESTER M3 8BB 

PLEASE RUSH ME A COPY OF 



ZX81 

n6ki 



VIC 20 2X SPECTRUM 

(Any Memory) () 6k or 48k} 



Monster Muncher 
Galaxy Invaders 
Missile Attack 



D 



D 



D 



D 
D 

n 



• SPECIAL OFFER THIS MONTH - SAVE ON TWOII 
SAVE £2.00 ON ANY 2 GAMES - PAY ONLY £9.00 

I enclose a cheque/P.O. for £ 

or please debit my Access Card. Expiry 

No. naanDDDDanaDDDnn 



NAME. 



Address 



FRBCPOST - NO STAJ^P MBCCSS^JIY 




^H EDITORIAL AND YOUR LETTERS: 28 days that shook the Spectrum now shake 
fcO Oric; breaking into schizophrenia; and our cynical view of advertising claims. 

^H NEWS: £100 colour computer from Creativision; Texas £75 16-bit micro; losing a job 
vll and winning a place in our Top 20; Firth's first BBG Forth; Tomy's £160 Grandstand. 

NEWS EXTRA U.S.A,: New micros galore, Intellivision gets brighter while a new age 
dawns for Mattel with Aquarius — the only £130 colour micro with plug-in Hintstones, 

COMPUTER CLUB: Simon Beesley — our man in the bearskin and snow-shoes — 
discovers a lost tribe of Nascom owners alive and well and living in the West Midlands. 



33 



37 



38 



40 



44 
50 



FIRST BYTES: If you have not passed Go with your brand-new micro go straight to 
First Bytes to collect an introduction to microcomputing and perhaps win £15 of software. 

ORIC V. SPECTRUM: THE SHOOT-OUT: Sinclair was bang on target with the 
Spectrum last year but will the town be big enough for both now Oric is here? 

£150 COLOUR PRINTER: Kathleen Peel reviews Tandy *s CGP-li5 four<olour 
printer which will plug into any computer with an RS-232 or Centronics interface, 

BBC SOFTWARE SURVEY: Blast your way out of the arcades with Rocket Raid or 
just calm do wn and admire the economy of a word processor on a chip. 

MOZART LIVES: Not only the first program to bring Wolfgang Amadeus back to life 
but also a hardware add-on which can make your Spectrum sound less like a damp squib. 



54 

M DRAGON MAGGOTS: Percy's performing Maggots will have them writhing in the 
aisles in this brilliantly simple game of lightning reflexes for the Dragon 32. 

CO ACE FOR GAMES: FORTH P AC-MAN: Forth is not just for high-speed calculations 
PO as Ralph HUton shows with this arcade ga me for the Jupiter Ace. _ _^ __^ 

yil INCREDIBLE SHRINKING COMPUTERS: John Dawson sums up 35 years of 
# U computer technology — from making noises in troughs of mercury^ to silicon chips. 

^C ZX-81 MACHINE-CODE EDITOR: Trevor Hill presents a user-friendly yet truly 

i V comprehensive monitor for the Sinclair ZX-81- 

HI VIC-20 POLYPHONIC BOOGIE: Adam Maciclinski squeezes a honky-tonk piano 
O I complete with graphics into the 3.5K of an unex pandcd Vic. 

M SPECTRUM WORD PROCESSOR; A complete machine-code word processor for the 
Spectrum by Stuart Nicholls which even lets > ou create your own type founts, 

Qfl BBC MONITOR: Space is of the essence in the BBC and Richard Harris has managed to 

97 



fit a commercial-quality monitor into just 2K including a full disassembler. 

BBC ASSEMBLER: The BBC Micro has the advantage of a built-in assembler but few 
people know how to lake full advantage of ii. Chris Melville advises. 



100 



LANGUAGE LEARNING ON THE ZX-81 AND DRAGON: The Brains show 
how you can use a micro to help you with French — or even Welsh — homework. 



1 117 ^'^*^^ ERROR: When your desk-top Dalck starts screaming "Error" at you do not 
I II # panic — just change the error messages to something more helpful. 

BASIC DICTIONARY; Tony Edwards takes us from Proc to Tab as he ncars the 
end of his marathon voyage through the Basic lexicon. 



Ill 



H| 4 ^ RESPONSE FRAME: Tim Hartnell tells you how you c^n differenriaie 16K from 

115 



48K SpectrumSj gives scrolling tips and tells you how to deal with large ginger cats. 

FINGERTIPS: POCKET COMPUTERS AND CALCULATORS: David 

Pringle with another selection of programs to fit your pocket. 



121 



139 



SOFTWARE FILE: 10 program-packed pages full of games^ tips> and serious 
applications for the Ace> Atom> ZX-Slj BBC> Vic-20, Dragon, Atari and Spectrum. 

COMPETITION CORNER: Another exploding puzzle - Telepathic Dangers: a 
winner for the Oric competition and the result of the Star Stone teaser^ 



llif IM A I VlilY ^^^^ complete the crossword and think of a slogan to win this 
VVIIV §\ Li 1 IM/V 48K colo- • computer — card between pages 26 and 27. 



^ 



YOUR COMPUTER. MARCH 1983 



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£%^ 



Starts atWKai^ 



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Panda, 
n seconds! 



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The 2X-PANDA is aptly named. 

Not only is it an excellent 16K RAM PACK for the ZX8I, but it is 
uniquely expandable at any time to 32K by the addition of an 
expansion module! 

' The ZX-PANDA is contoured 
to (it periectiy on your ZX8L 
No wobble. No whiteouts! 




So you can start with I6K . . . and grow bigger later! 
2X-PANDA gives you everything you need from a professionally 
produced RAM PACK:- 

Full 16384 bytes of extra Random Access Memory. 

Expandable further to 32K by simple 'plug-in' module. 

Custom made case contoured to fit snugly on your ZX81. 

Power-on LED. 

No additional power supply needed. 

Compatible with most expansion systems. 

Designed and built in Britain. 

Fully tested and guaranteed for 1 year. 

ZX-PANDA is the RAM Pack to choose for your ZX81 expansion, 
because, when you want to grow bigger than 16K . . . it couldn't be 
simpler! 



The ZX-PANDA 16K 
Expandable RAM Pack 
is available through the 
following retailers: 




Available in the U.K. at: 

Greens at Debenhams(all branches). 

Wigfalls(al! branches). 

Artie Computing (Hull). Microware (Leicester). 

Data-Assette (London). RAM Electronics (Fleet). 

Afdec Electronics (Basingstoke). Buffer Micro Shop (Streatham). 

fox Electronics (Basingstoke), and other local dealers. 



STONECHIP ELECTRONICS 

ZX-PANSA 

16K EXPANDABLE RAM. 



ffK tinikcr iifontita, plim wnte to STOflECHtP tUCTlOMICS. TUf Biook lo^ustriil tsUtt . \kk4bmk Unc, 





\ 



THE PROGRAM IHATS LEAPS 



AHEADOF 



THE REST. 




THE MOST FANTASTIC 
ACTION GAME FOR 
THE BBC MICRO! 

FAST ARCADE PLAY! 
MODE 2 COLOUR GRAPHICS 
AT ITS BEST! 
FIVE TUNES! 
INCREDIBLY ADDICTIVE! 

AVAILABLE NOW 

AT YOUR SOFTWARE 
FOR ALL DEALER 

0Niy£a95 



SEE IT NOW AT YOUR NEAREST SOFTWARE FOR ALL DEALER! 



A6ftCC0MPUT€R$ 

St Austt^l 

Cof nwaH PL25 30W 

Tet: 072664463 
BLADEN COMPUTER SYSTEMS 

22 Gtynne Street 

Fam worth. Bolton 

LancsBL4 0Y 

Te! 02CW7W226 
BYTEWAREITO. 

unit 25 

HancJyside AfcatJe 

^8wcastfe On Tyne 

Tef 053?6t7t11 
CARLTON COMPUTERS LTD, 

4 Swaastons Road 

Gt Ya^fTcuin 

^0toikHR303NQ 

1*1.0493 58898 
COMPUTERS FOR AIL 

72 North Street 

ftomford. Essex 

Tel 0708 75286? 
COMPUTER PLUS 

47 OuMHs Road 

Witfofd 

Herts WOl 2LH 

Te)C923 33927 
ESSEX COMPUTER CENTRE LTD. 

150McnjtshamSlfecl 

CI\efmsfof<J. Essex 

Tel 0245358702/87969 



FAREHAM COMPUTER CENTRE 

Farcham. Hants 

Tel: 0329 2^9191 
GAMES WORKSHOP 

1 Oi'img Road 

Hafnmers'nith, London W6 

Fei: 01-741 3^45 
GAMES WORKSHOP 

i62Mars4enWiy 

Amitale Centre 

Wartchester 

Tel: 061-832 6863 
GAMES WORKSHOP 

Unit 37 

Bffmingham Stiopptng Centre 

Bianmgham B2 

Tel: 021-6324604 
GAMES WORKSHOP 

95 The Moor. Sheffield 

Tei: 0742 750114 
MANSFIELD COMPUTERS & EUC 

79flaic!i^fcGaie Mafisftcld 

\ons. SG!a2JB 

Tel 062331202 
MICROSTYLE 

29 Belvedere 

Lansdown Road. Bath 

let: 0225 319705 
RAM ELECTRONICS 

106 Fieet Road 

FSeet, Hants. GU 13 8PA 

Tel 02S14 5858 



RDS ELECTRICAL LTD. 

157-161 Kingston Road 

Portsmouth 

Hants P02 7EF 

Te5: 0705 812478 
R.M.K, ELECTRONICS LTD. 

Hinton Hojse. Station R03O 

New Mirton 

Hants. BH236HZ 

Te» 0425 616110 
STORKROSE LTD. 

44 Shrclcn Stree? 

London NWl 

Te;: 01-258 0409 
SUPERIOR SYSTEMS LTD. 

1 78 Wes? Street 

Shetliew 

Soiiin Yorkshire, SI 4€r 

Tel: 0742 755005 



TEGHNOMATICLTD. 

17 Burntey Road 

London NWIO 

Tei 01-4501500 
WATFORO ELECTRONICS 

33-35 Cafdfff Road 

Watford 

Hefts WD1 880 

Tei; 0923 ^0588 



DistfibtitOf for Holland. 
8e(gium&Luxen!t)our9: 

AACKOSOn 

pDstbus3ni 
2301 DC LeKJen 
Tel 01880*1446 




SOFTWARE 



FORAfeb»< 



Vmgiwnsfbrthepeople^ 



YOUR COMPUTER, MARCH 1 983 5 



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tATARI OWNERS!!! I 

The POWER of the grid ^ 

is with YOU! gj 

Now available for- ^ 
ATARI 400/800- 

16/32 /48K _. 

GRID RUNNER m 

ful 

Play the bestselling — 

VIC /COMMODORE 64 
game on your ATARI. 
Discover one of the 
FASTEST, MEANEST 
and most compulsive 
SHOOT-EM-UPgames 
ever devised ! 
100% Arcade quality 
machine code -supplied [Q| 
onAUTOBOOT TAPE Ql 
CASSETTE -guaranteed Ql 
to wearyour joysticks out! [3I 
Don't pay ATARI prices BJ 
for ATARI quality! Bl 

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Suj^ Qi^^JjUi^ ic^^ ^LLAMASOFT* g 




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(DESIGNER — JEFF MINTER) 



VIC 20 



ABDUCTOR BUS! J 

A classfC riew space game! ZAP the swiding aUen hOfdes before they ram you — ancf 
aMuct /our humanokJs* Surv^e the assault (or tong enough and you il get an extra stage on 
your spaceship with cJoubte firepower? Awesooie unexpended Vic Action. £6.00 ^ 50p 

GRIDRUNNER Kiagl j 

Finally, true afcacJe quafrty on the unexparded VIC! Shoot down the segmented DROIOS 
invading the grid. Beware o( the pods and zappors* The awsome speed, sound and 
graphics gives you tho best t>last avat^able for un^xparxJed V»c. Ce.OO * 50p P^9. 
ANDES ATTACK (8K) UTaPl J 

Your spacecraft must attac*< the descer>dtr>g al*ens and frustrate Ifwir evil intent. Ry your 
Ramjet fighter over the Andes mountain range and protect your llamas from kidnap by 
hosttto UFOS. Features 5 kinds of UFO, controls if>clude up, down, reverse, fire, thrust and 
smart txKnl). Entirely m machine code. Requires 8K expanson and joysifCk, £8.00 + 50p 

TRAXX M/C (8K - EXPANSION) J 

This is VIC 20 cross t>^eed between the now famed PacKn^an* and the game Quix*. All in 
machine code, fast arid fun with joystick controis. uses Hi*Res colour graphics. 8K or larger 
expansion needed. Only £8.00 * SOp P^P complete with Instructions* 



THE VERY FIRST COMMODORE 64 GAMES 



ATTACK OF THE MUTANT CAMELS J 

Ranet earth needs you! Hostito aliens have used genet*c engrneonno to mutate camels 
from normally harmless beasts mto 90 foot h^gh, neutronium shielded, laser-sptting death 
camels'! Can >^ou fly your tiny, manoeuvrable f ghtcr over the mountainous landscape to 
weaken afKJ destroy t^ie camels before they :nvade the human stronghold! You must 
withstand withering laser fire and alien UFOs, Game action stretcfies over 10 screen 
lengths and features superb scrolling, scanner, 12 player actions and unbehevable 
anin^ationl Play this game and you'll never be able to visit a zoo again without getting an 
itchy trigger tjnger t Awesome mc action* £8.50 -•• SOp P^P, 
ROX-64 

Rox ts a chaitengirvg game involving the defence of your lunar base from a deadly meteor 
shower. Rox-^ includes amazing spote graphics displays and spacy sound effects, and an 
awesome nfwthorship' display i1 you win the game- Top 10 scores are tabled along with their 
names. This program shows just vrtiai can be achieved using onty ComrTKJdore-64 basic. 
Stud/ trie irsfrng and learn how to use sprites and sound on this outstanding machine. 
£4.95 + sop PLP, 

GRtDRUNNER 64 J 

The No. 1 best gamo tor the Vk: has been irr^roved for your COMMODORE 64! Gridrunner 
is a smash hit in the USA. f4ow expener>ce the iightnnQ-tasi chaitenqe ot tne fjno on the &4. 
Features 31 skjii levels and excellent sound and graphics. Sore trjgger finger free wrih every 
game' £S.50 + SOp P4P. 



J = JOYSTICK CONTROL 



SPECTRUM 



GRAPHICS CREATOR (16K) 

Not lust another character editor? Allows you to define not only the 21 user definable 
characters. Also aiJows you to change the entire 96 character ASCtI set. Creates BYTES 
files ready for you to load in:o your own programs. Includes advanced Reflect. Invert Field 
commands etc. Complete w;ih full documentatton. Bin the 8IN statement and use G'aphics 
Creator with its easy on-screen cursor editing. £2.05 + SOp PAP. 
BOMBER (1GK) 

Yes, a full feature version of the popular game Blitz', supplied for the 16K or 4$K Spectrum 
For only E2.95 * SOp P&P. 

HEADBANGER (4dK) 

Colourlul Trow game stamng Chico the neadbanger who you must guide to riches through 
an increasing shower of heavy metal. Gain bonuses for headbanging but be sure to take an 
aspinn when the pa»n gets too much! Baste + nnc to speed up action. Great graph^^, nice 
animation. Wil even drrve Wii:iam Stuart system's vo^e synthesiser to produce speech 
output. C^r\ you attain the grade of 'RocKer Class One' or will you be ^'Barry Manilow Class 
5? Start head Dang ng to day and find out. £4.95 NEW. 
SUPEROEFLEX (48K) 

Bounce Sid , the space invader, around the screen into the power pods, Keeping away of 
course from the devji who chases you around the screen. Steer with your Deffex shields, but 
beware tho mines or you may be buried aliver Superb graphics and farttastic sound on the 
48K Spectrum on!y. Only £4,95 on castene + SOp P&P. 



ATARI 400-800 



TURBOFLEX 

Superb uttra-fast and totally new bail game. Uses ATARI'S unique features to the full. 
Incorporates superb cotour sound effects and uses PlayerMissile graphics Tabtes top 10 
scores along w,lh Scorer s name CS.OO * SOp PtP, 

GRAPHICS CHARACTER CREATOR 

Now you can define your own custom character sets, or edrl existing sels. Results are fully 
displayed on screen in modes 0, l , 2. Special features include reflect, invert, save character 
sets etc. Supplied on cassette with data sheel only £8.00 i SOp P&P. 



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ZX81 



CENTIPEDE (leK) 

the ORIGlMAU game from the ORIGINAL author. 
Thts IS the identtcal program to that being sold by 
other companies for three times our pnce. The 
game has received ecstatic reviews in the comput- 
»ng press. Program has 30 speed levels and ever 
increasing Centipede nordes< Tables top 10 
scores and names. Why waft to pay more*? Only 
£1.95 * SOp P&P. 



Please add SOp P&P with all orders 



LLAMASOFT 

SOFTWARE 



] Oopfl. YC 
4d Mount RtasJtnt, 
Tadley. Kants 
RG26 6BN. 
Tel: 0735€-447a 
Trade eitqulKas 
walcome. 




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BJ 

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6 YOUR COMPUTER, MARCH 1983 



100 FREE PROGRAMS 

FROM SILICA SHOP — WITH EVERY PURCHASE OF AIM 



119 7dBil 9791 



«....--.,.-. ^^ifl 



'rt— — — _ 



'"^'^''^^4^. 



^ - >v 



ATARI PRICES REDUCED 

We at Silica Shop are pteased lo announce some 
fantastic reductions in the prices of the Atari 400 800 
personal computers. We believe that the Atari at its 
new price will become the U.K.'s most popular per- 
sonal computer and have therefore set up the Silica 
Atari Users Club. This club already has a library of 
over 500 programs and with your purchase of a 400 
or 800 computer we wiH give you the first TOO free of 
charge. There are also over 350 professionally writ- 
ten games and utility programs, some are listed 
below. Complete the reply coupon and we'll send 
you full details. Alternatively give us d ring on 01-301 
1111 or 01 309 1111 



ATARI 400 

with 16K 



£199 



ATARI 400 

with 32K 



£248 



ATARI 800 

with 16K 



£449 



400/800 SOFTWARE & PERIPHERALS 

Don't buy a T.V, gamef Buy af^ Atari 400 personal computer and a game cartridge and that's all you'll need. Later on you can buy the Basic 

Programming cartridge (£35) and try your hand at programming using the easy to learn BASIC language. Or if you are interested in business 

applications, you can buy the Atari 800 * Disk Drive ^ Printer together with a selection of business packages. 

Silica Shop have put together a full catalogue and price list giving details of all the peripherals as well as the extensive range of software that is now 

available for the Atari 400 800. The Atari is now one of the best supported personal computers. Send NOW for Silica Shop's catalogue and price list 

as well as details on our users club, 

THE FOLLOWING IS JUST A SMALL SELECTION FROM THE RANGE OF ITEMS AVAILABLE: 



A£»;£»$)«m$ 




BUSINESS 


C«btci 


ttt4«>9u«d 


C«)ait«iof 


CM»eit*t 


Si»f Fht* 




Oitkettn 


s«rtd*vGo)t 


DtCiiion M«ktr 


Mtt*cM 




<jf«pl>U 


U SiKh • Jovitick 


AUTOMATED 


Inv0<»n9 


Miic Supptitt 


S4MUUVTI0NS 


UtXAfc^n 


l>«ddm 


Cfuift Crufnbl* Cmp 


Mof 1 a LO^ Am* 




OjleitOr«t of Ryn 


l^O«ntn«l \A&gtf 


AOVfNTUKt INT 


DrdOoni Ey* 


RaV'o" 


Scon Ad imt Adv 


hvvMJOft O'lOn 


^«f*0P4« Finl Mflmi 


^t A,*y*ntyfe;»>d 


Rrt<vr 41 R>9«t 


P\jf£h»i« Udg*r 


No 2 ^tf «T* Adv 


RicocKrt 


SjI*i Led^w 


No 3 WfMkOn Irrp 


5l«f VV^r«or 


S!4l*fT<t 1 


No 4 Voodoo Cait 


Tfvnpl* or Apt^•l 


S:ocit Cofitrol 


NoS Th*C«wnt 


Upptr Rfjchci Apt 


THclmk t 


Noe Ufm^0&4 




Vi«tc*k 


NO 7 MviWfv Fun 


BOOKS 


W»*lc/v Pr^nmr 


No 8 Pyi^KJofO 


e^K ftf f M*nu»4 


Word Pvoctt»Or 


Nod GhoftTowr 


Compute At«r* OOS 




No 10 Ssv rilarKt \ 
No 1 1 S»tf lir«fKt 2 


Compute flk At*f 1 
ComjKit* W*0uin« 


CftYSTAtWARE 


No 12 Goldff) Vov 


0« R* At«ri 


Firti«Vl*rtd204t 


An«te Wdrmi 


DOS UMitiet U»t 


G«lKtie Q^iT 


Dttl«ct^o<^i 


0OS2VUmi«l 


MowifOlUihef 




Mttc At«n 8ooki 


S*^t Of %»Af\ 


GalACtic Trtdtf 


Op SvtHyn titling 


WtttfJoo 


Ufiw Lirtdrr 


Wiltv PUlw>»ii 


IVofIdW*r in 



A]pfi« FrgMtr 

CrviUd 
Fofeil Ftrt 
Inirudvr Ai«*t 

Moof«ro6« 
Movfig M«2t 
Nommo«i Ji^uw 

Riftgf of Th# Emp 
Sp»0»Tiit 
SpMt frip 
Stvd PioM' 
Tr.pt# B^ock»d# 

EDUCATION 

A%K«lC 

AiIm of Cifkjda 
Cg&bvKot*! 
efrm«Ai*rv BiOf09V 
FroQm»ttfr 
HickOrv Orcicorv 
Imt Co^pt9 Dfn 
Lff^OAAdi 
Lt!t#rm*rt 



W#!h|T»c Tot 
V4tr»c &ProbSoN9 

Mum Ttfmi/Notitrb 
Muti««l Computif 
Mv Firn A^MUt 
Niimb«r Blaii 

Potve«k 
PretKtenu Of U S. 

Qui; M4lt«f 

Sif'toaOCriQiiKt 
Thrt* « Mjth Sy^ 

Video %M\t\ Fi*i^ 
Wofdmiktf 

gPygATjOfj 

tum^tABJ 

Conv Frtftch 
Cortv C4fm*r» 
COrtv \\%i\tt> 
Co^v Sf»«nUH 
Energy 0»r 
EgroptJrt C Si C«Pf 

fnvtt To Prog 1/2/3 
Ki^odOfn 
Mutjc Composer 



Scfim 

St«t»f h C«>itBll 
To<.>ct« Typ«fl 

fMlSOfTWfARE 

Sfitrth H«4ii«i9e 
Cr J bl>*Q«/ Dom*<YO*t 

€urop«*n Sc«r« J*j 
M^kOfv 0*ekOrv 
Kumpiy Oumpty 
Jvfli«>o J*i Lirwief 
Soook*r & B»llt«fdi 
Sub«n*f in« Commdf 
S^pf CMMt & Tilt 
ToufTvimf At *^ool 

frgflLAEtS 

Alttn E0O 
A^tfiifr 

Ait»nfc 
Av«l«i^c^ 

dtAchiacic Cat«no 

Qlock Bulltr 
fttock Cm 
Bumper Pool 



CHtk 

Cinturon 

Chfck*rKtf^ 

ChtneM Pu^fle 

Codc^facker 

Comtdv Oit^ietit 

Ok* Pofcef 

Doo[>«ee 

DomiA«tion 

DOvvrihrU 

Etfterr Frooi 

GifAhMt h Holy Cfl 

Criph*c4rSovr^ 

JflxO 

A/kebPx 

Look4h««d 

Mcmo<v M*ieh 

MidM ToucK 

Mtfvotf>^r 

Outlemi/Ho'mtter 

Preicf^ol GvTTfi 

Pro Bowling 

Poihovtf 

RibbOit 

Rfvfrtt II 

Sitmon Run 

747 L*ridiOpg S*m<u* 

S«vef^ C*rd Stud 



Sfeuv Adyetiture 
Solitaire 
Sp««> Chftte 
Space Trek 
SMll4^|ftlac« 
T»ci Trek 
Terrv 

tJVri»fdt Go<d 
Vixtm^i Rcv«nge 

eNjrtRrAINMCNT 
W^>m ATAWi 

AitffOKH 
Baikett>»ll 
Bi*ck:«:k 

Centipede 

£nt«fT«irwTvrnT Kit 
V»iiij# Comfntnd 
P#c V*^ 
Space Irtvadtft 
Ster Reidtft 
Supff BtfAkdut 
Wdeo Eetel 

ONLIN ESY STEWS 

C'Ottfire 
FrO«er 



JtM^)fe4ker 
MiM>ort Aneroid 
Vovtkatieck 
Threihokl 

Ulyiiei/Gotdtrt f J 
Wizard & Pf ti>«it«» 

fgftlPHJIftAU 

CenironiaPrlrtieri 
Oitk Orrx* 
£piOm Prmter^ 
Pro^rww Recorder 
RS232 Interface 
TMrmAi Prt^ite* 
ISK M«mory RAM 
32K Memory RAM 

PJLHSONAUMI 

(Mm A£X 
Adv MuK SvMtm 
aa<^n«' G4^eratOf 
8tackjack Tutor 
Go«rifl To Trte O091 
Keyboard Organ 
Moi'ife Co<f« Tutor 
Pe?to#ai F.tfte»Prs 
Waver Plar^o 
Sketctipad 



Asfpnbltf Etfitor 
DM«nt>ltr (APX I 
MicrOfPtt S*|*< 
P»K«I iAPXj 
Ptiot (Cemuenef ) 
Pilot (Eductterl 
ProQrivnmlrtg Kit 

SANTA CnUT 
BaitCf ©rArimifiton 
Bot>s Bus>r)rti 

Or«pl^ Urtll 

Crip«t»c« Macf^tft* 
Kid» 1 ft 2 
HOriiOAtal ScrOMir^g 
Maittf Mtmorv Map 
Mttfti Word Pvoc««lor 
P«Oa Flippirtt 
Player MiH«lt G» 
PTayer Ptarko 
Sourvdt 
Ve^tt^al ScO'lirfft 

SttlCA CUUB 

Over 500 pro(fjf«v| 
wrf 1 1< f o* rfe^*^ 



FOR FREE BROCHURES-TEL: 01-301 1111 



«*'*i-r-«^Oi K< I'll T« c<^il«» W «»«*h#i« j«V «i4(* rtt** ^ti*« w»»-vit 

> fciiMjj..jt * mf C e £i%M*Ct -»*u< I *£«■«« }«M9«rar*««ii».»'40««i«^ 

# l^ukp Wo'4«* ta 4.#»vJ** »*» to %J0»^ M«»«>|| Tfr«**a#. t»» 
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• VAli OAd* ** mm * «£«•:-« ^ *« Are** %a ^ H ** >% «*« «»• «»« w 

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m *%•* f (.>«•* ^w**n •»»<># '•^tvewvAtti »v. 

siLJCA SHOP uMrrco 

Dopt. YC0283, 14 The Mows, Hathortey Road, Skicup, 
KomDA14 4DX.To««phono01301 1111 or01-30i» 1111^. 



'""•-lirlll 

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FREE LITERATURE 

( am imefested in purchdt^ing on Atari 400/300 comp^tef and 

would itke to receive copies of your brochures end test repons 

as wcil as votjr price list covering all of ihe available Hardware 

I H and Software: 

h ■ Name. 

Address 

Postcode. - , — 

YC0283 - Your Computer - february 1963 



YOUR COMPUTEa MARCH 1983 




At Mem 
we realise the poten 



MEMOPAK 1 6K For ibose just setung 
out on the road lo real computing, ihis pack 
iransfomis ihc ZXSl from a toy to a powerful 
computer. Dan storage, extended programmiflg 
and cooipkx displays become feasible. 
For even grcaicr capacity, mctnon* packs can 
be added together 16+ i6K or 16+J2K). 
The MHMOPAK 52K aod the MEMOPAK 
64K offer brge memories at econom^a] prices. 





32K: £49.95 
64K: £79.00 

inclusive of VAT 




MEMOPAK Centronics i/F 

The BASIC commands LPRINT, LUST and 
COPY are used lo print on any CENTRONICS 
type printer. All ASCII chancien ait generated 
and translation takes place automatically within 
the pxk. Reverse capitals give ktwer case 
Additional f acilities al low high resolution priniiag. 
C39.90 
incVAT 



ZX81 



It all adds up to an efficient, 
modular con^uter system 




The Memotech approach to microcomputing is to take 
the well-proven and popular ZX81 as the heart of a modular 
system. This small computer houses the powerful Z80A 
processing unit and acts as the central processor module 
through which the Memopaks operate. 

Memotech has a reputation for professional quality, 
producing units which are designed to fit perfectly, to look 
well-balanced, and to work efficiently and reliably. 

The modular approach gives ZX81 owners the freedom to 
design the system they really need. Furthermore, the 
intcrcompatibiUty of the modules ensures that later additions 
will click straight in, to give you a system that grows with your 
ambitions and abilities. 

To ensure that your expectations are realised, care is taken 
at every stage to design features into the system to anticipate 
your needs. For example: 
1) Memories are cumulative e.g. 16K and 32K can be added 



to the Memopak 16K or even to the Sinclair 16K RAM pack* 
2) The HRG firmware allows commonly used constructions 
(such as scrolling, shading and labelling graphs), to be called 
by a few simple commands. 3) The Centronics I/F converts 
ZX81 character codes into ASCII and extends the print line to 
the width of the printer, still using the LLIST, LPRINT and 
COPY commands. 

As one example, a system with 16K of memory and 
Memocatc is all that is required to perform the same 
sophisticated numerical projections as a computer at 10 times 
the price. The problem may be as complicated as a cash flow 
or production schedule, or as simple as household accounts or 
pocket money budgeting. If your bank manager wants to sec a 
cash flow, then a single print instruction to the Centronics I/F 
will give a printout which is more than acceptable. 

The example system which is shown, on the other hand, 
would satisfy the needs of someone who wanted to enter data 



How it all fits together 

I 



You can set from the diagrams how various 
Memotech Sinclair units can be combined. 




KHor32HorMff 



»^^»*** w t.^i 1,111 i^r^^-^^ 




8 YOUR COMPUTER, MARCH 1983 



otech, 
tia l<rfy<mrZX81 




MEMOCALC Iht soeeD display behavts 
35 a Viiidow' Oft a large sheet of pap^ on 
which a table of numbers is bid out. The 
maximum size of the table is deiennioed by the 
mcmon* capacity, and with a MEMOPAK $4K 
a labk of up to 7(X)0 numbcn with up lo 250 
rows or 99 columns can be specified. Each 
location in the table can be either a number 
which is keyed in or a formula which genentei 
a number 
£29.90 inc VAT 



ncnocaLC 



-'I 



MEMOPAK HRG This pack breaks 
down the voni;rainis imposed by opt rating at 
the ZXSl character level and allows high 
definiiion dispiav^s to be generated. All 24S x 192 
iodi^iJuai pixels can be controlled using simple 
commands, and the built in software enables 
the user to work inieraciively at the don, line* 
character, block and page kvth. Scrolling, 
tiashing and animation a re all here . 
EaS.MIncVATl^^ 





I 



MEMOTECH KEYBOARD 

Xh.€ Mcnwicch plug-in Keyboard plus buffer 
pack lakes the effort out of data entry for ZXSl 
users. The Keyboard has a bghi professional 
louch and is housed tn m elegant alummium 
case. The simple ptug*m system oKans thai you 
are not obliged to open up your ZXSl , use a 
soldering iron or invalidate wur ZX8 1 
wanantv. 
£49.95 inc VAT 




via a light-touch keyboard , construct and label graphs, and 
then copy the screen to an 80-column printer. Only 16K of 
memory is shown here but with additional memory, more than 
one video page can be stored. Up to 7 pages can be displayed 
in rapid succession to give animated displays. 

Looking forward, Memotech will continue to back the 
ZXSl through 1983 with fast storage devices, pressure sensitive 
electronic drawing boards and more software packs including a 
Wordprocessor, an RS232 Interface and a Z80 Assembler. 



KEYBOARD BUFFER PAK 
The Buffer Pak performs a * 'housekeeping" 
function for the Keyboaid. interfacing directly 
^iih the port ai ihe kKkof your ZX81. 



J 



To: Memotech Limited, Witney, Oxen, 0X8 6BX 

Tel: Witney 2977, Telex 83372 Memtec G 
Please send me the following Memotech products: 



Please add C2.00 
per item to cover 
post and packing 



enclose a cheque/P.O. for 

or please debit my Access/Barclaycard account number 



Signature 



.Date, 



Name and Address . 



r« 



YOUR COMPUTER. MARCH 1983 



il 



(H) 




Hewson Consultants 

We proudly announce our 1983 range of 
SPECTRUM CASSETTES 

NIGHTFLITE 16 and 48K FLIGHT SIMULATOR 

NiGHTFLITE puts you at the controls of a 

tight aircraft flying at night. You can: 

Climb, descend, take off. 

Land, bank left or right. 

Navigate between beacons. 

Raise/lower thef laps. 

Raise/lower the undercarriage. 

Adjust engine rpm, 

Rarse/lower the nose varying amounts. 

Runway lights appear on approach. 

5 modes including Autopilot. 

Written by a qualified light aircraft pilot 



A/H 


-artificial horizon 


ALT 


- altitude in ft 


HDG 


- heading in compass degrees 


FL 


- flaps up/down 


GR 


-gear up/down 


vst 


- vertical speed indicator 


WfND 


- wind direction/velocity 


OME 


- distance measure equipment 


ADF 


- automatic direction finder 


ILS 


- instrument landing system 


VOR 


- VHFomni directional range 



£5.95 



our runaway best seller 



Available through W H SMITHS and many independent micro-computer shops 



COMING SOON:- AIR TRAFFIC CONTROL-Putsyouincommand at Heathrow Airport £5.95 




i 



MAZE CHASE 

16and48K 

4 or 8 Mazes, Highest score to date, 
4 independent guardians, 3 lives. 
Full colour. Fast machine code action. 



£5.95 

All action ganne 



£5.95 

Are you 
fast enough? 



► 




SPECVADERS i6K 

Defeat each squadron of Beeple Zaps 
and another appears only closer, 
Cyrian mothership with ejecting Zeetle 
Baps. 



5 levels of play from Orions snails pace 
to close you r eyes and hope. 
Real tinne scoring. 3 lives. Pan galactic 
gargle blaster for highest score. 
Descending asteriods. 





riiiiiii-^ 
■11 ?| 






J 







i 



BACKGAMMON igk 

8 Levels of play from novice to expert. 
Full colour display of tables and dice. 
Gamble on a single game or a series, double or 
quits. All the features of the ancient game. 

10 YOUR COMPUTER, MARCH 1983 



£5.95 

A real challenge 

£5.95 k. 

Another first ^ 

COUNTRIES 
OF THE WORLD 

16 and 48K on one cassette 
Countries of the world is an 
educational package designed to give 
an appreciation of the location of all the 
main countries and some information 
about them. 
16K version displays a world map. 




shows the position of each country and 
names its capital. 

48K version; all the above plus prints 
the population, size, currency and 
main languages of each country, and 
statistics on largest and smallest 
countries etc. 




Hewson Consultants 

SPECTRUM BOOKS 











40 BEST MACHINE CODE ROUTINES 
FOR THE ZX SPECTRUM 

By Andrew Hewson and John Hard man 
Section A: Three chapters explaining what you 
need to know about Z80 machine code on the 
Spectrum. 

• How to load and save machine code. 

• How to use the system variabtes. 

• How memory is organised. 

• How program lines are stored. 

• How to use the stack, the display, the 
attribute files. 

• Howtocall ROM routines -where they are 
and what they do. 

• The structure of 280 code - plus a valuable 
glossary. 



£5.95 

Section B: 40 routines including, 

• Scroll - up, down, side to side by pixel or by 
character. 

• Search and replace, token swap, string 
search. 

• Rotate character, invert character - 
horizontally and vertically, 

• Line renumber- including GOSUBs, 
GOTOs/RUNetc. 



This book teaches the beginner all he needs to 
know m a simple, easy-to-learn form and its an 
invaluable referenceworkforthe expert tool 



20 BEST PROGRAMS FOR THE ZX SPECTRUM £5.95 



'-^^k«3ncM vcrocH 



Available through Computer Bookshops 
and WH SMITH. 



By A n dre w Hewson 
Program titles include: 
MachineCodeEdilor-Write, modify, extend 
and load machine code using this all-basic 
program. No uB^d to use an Assembler when 
you have this program- 
Index File - Learn about fixed length records, 
save numeric and string information, add to. 
sort, modify, delete and print your records. 
Ideal as a computer based filing system. 
Duckshoot- Learn howto manipulate the 



attributes file andhave fun at the same time. 

Graphix - Construct up to 210 graphics 

characters with the full on-screen editing 

facilities, enhance and modify them and recall 

them later to build a detailed display to save on 

cassette. 

Spiromania -^ A program to stretch your artistic 

talants, imagination and ingenuity. Draws a 

limitless variety of curves and spirals. 

Plus: FOOTBALL, DIGITISER, DIARY and many 

more. 




ZX81 
BEST SELLERS 



PILOT 16K(ZX8i) £5.95 

Fly your own aircraft. 

Instruments : 

Artificial Horizon, 

Automatic Direction Finder, 

Instrument Landing System, 

Readouts: 

RPM, Flaps, Heading etc. 





PUCKMAN 16K(zx8i)£5.95 



HINTS & TIPS FOR 
THEZX81 £3.95 



Passing data between programmes. 
Calling subroutines from cassette. 
Machine code programmes. 
Bits, bytes, addresses and hexodecimal plus 
much more. 



3 Mazes. 

Highest score to date. 

4 Independent guardians. 
Magic strawberries. 



RETAILERS 

We are continually on the look out for new 
outlets, if you are interested in stocking 
the items advertised here, write to us for 
our trade rates. 



URGENT 

We require high quality Spectrum and 
Dragon software. Good royalties paid. 
Send your samples today for fast 
evaluation. 



THE PROGRAMS 

The programs advertised here are 
available from computer bookshops with 
a software stand, and many independent 
micro-computer shops. 



■ 


w. -w . 




ORDER FORM Make chtmues/POs payable to 

Hewson Consultants ' 

QuarYtity Product 


YC3 1 

Cost 




























• 




Name Tntal 




m«ock Capitols Pleased 

AfJdress 



-_ Signed, 



My Access/Barclaycard No. is . 



Post to : HEWSON CONSULTANTS, 60A St Mary's Street, Waliingford, Oxon 0X10 OEL 
I Tei (0491) 36307. 

YOUR COMPUTER. MARCH t983 \ 1 



I 



INTEREST 

FREE 

CREDIT 

NOW! 0N> 





If your order contains over £120 worth of computer 
hardware apply now for interest free credit by telephoning: 
Mail-order: (0702) 552911. London Shop: 01-748 0926. 
Birmingham Shop: 021 -356 7292. Southend Shop: 0702 
554000 or write to P.O. Box 3, Rayleigh, Essex SS6 SLR. 

You pay 10% down, then 10% per month for a further 
nine months (to nearest penny). Example: Atari 400 48K. 
Cash price £299. Credit terms: £29.90 down, then £29.90 
per month for nine months. Total £299. Credit quotations 
on request. This offer subject to approval which can take up 
to 48 hours (APR = 0%). 



THE NEW COMMODORE 64 

The incredible new computer from Commodore comes 
with 64K RAM fitted! Plus 16 colours hi-res graphics, 
320 X 2CX) pixels, 40 columns by 25 lines, Z80 micro 
processor can be added — that means you can run CP/M 
software, 8 independently movable Sprites with collision 
detection, and a sound generator with 3 voices, 4 wave- 
forms, envelope and filter to rival some dedicated music 
synthesisers. And all this at the most incredible price ever 

(AF56L) Only £339.00 



DRAGON 32 




The amazing new British computer 
with a full-travel standard keyboard, 
a 16-bit microprocessor, 32K RAM 
fitted (expandable to 64K and later to 
256K!!), 9 colours, hi-res graphics 
and Microsoft extended colour 
BASIC (the very best BASIC to learn 
with}. It can be used with virtually 
any ordinary cassette recorder, it has 
a printer interface (Centronics-type), 
joysticks are available and it's in- 
credible value for money. 
(AF57M) Only£199.50. 

Lots of new Dragon software 
available. 



THE AMAZING ATARI COMPUTERS 



4 Consoles Available: 
Atari 400, 1 6K RAM (AF36P) £249.95 
Atari 400, 48K RAM (AF37S) £299.00 
Atari 800, 1 6K RAM (AF02C) £399.00 
Atari 800, 48K RAM {AF55K) £440.00 

• All above with BASIC & handbooks 
Carriage free, delivery next day 
by Datapost 



Other hardware: 

Cassette Recorder 

DfSk Drive 

Thermal Printer 

Epson MX80T Mk III 

Epson MX80F/T Mk Nl 

Printer Interface for 400 

Printer Interface for 800 

Interface Module 

Versawriter 

16K RAM Module 

48K RAM Module for 400 (AF44X) 

48K Upgrade for 400 <AF45Y> 

Floppy 0»sk (YX87U) 

Le Stick (AC45YI 

Joystick Controllers (Pair) (AC37S) 

Paddte Controllers |Pair) {AC30H) 



(AF28F) £50.00 

(AFOeC) £299.95 

(AF04E) £265.00 

(AF38R) £399.95 

(AF40T) £447.35 

(AF41U) £59.95 

(AF42V) £59.95 

(AF29G> £135.00 

(AF43W) £199.95 

(AF08J) £55.00 

£99.95 

£75.00 

£2.50 

£2495 

£13.95 

£13,95 




t i^9» EB €B €B fS €B n A«l<^ 



CSJ CsJ & J S C^ ISJ I 



•*L-^ 



IM : 
Id fsm 



^^\mm\w\\\\\y\w\\\my 



^ 




For full ddtfttis «»k for our hardware laaflat (XH&4JI SAE appractatod 

JOIN THE U.K. ATARI COMPUTER OWNERS' CLUB 

An independent users' group Four issues of the club magazine for only £3.00f Address your subscription to Ron 

issue t of The club magazine featured a tutorial on character set redeftnitton and contained a collection of demonstratton and 

games programs and lots more. Issue 2 featured a tutorial on player/ missile graphics, anafiicle about graphics on computers, a 

selection of members' contributions to the program library and much more. 



THE FINEST SELECTION OF ATARI SOFTWARE 



C<^»«''*«t«A4i r»#Aeh 
C«r.-» « f li! ton* I Cef i^*n 

Sf«tH a C»pit9>« 

EuroCojfHr^v & Ch^oAv 

>nv«J1>on To frogritvTkrvg 2 
\r*f%tt,Miti To ^«grainming 3^ 

«Pl*y«f M«»W« G^dptit^* 

• Tf <fcv TMOtoH FrfM 6 
P»9«6 

BufafMft Prog^tmf 



SC 1«K 
-6C-16K 
SC 16K- 
SC 16K 

1C xw. 

!C fCK 
IC I6< 
ID 32IC 



YC44)( 
yG46A 
VG490 

vGses. 

VGS7M 
aCODA 
aG02C 
Ke23A 



£39 95 

£39 9& 
£3t» 
£1dW 
£!4 95 
£t4» 
£n 7i 
£11 75 
£29 SS 



Ai^t VVtHxJ P*««*Wf IC*30^ft8K YG42 V £99 35 



IC-eiC-VGOV/ £19 9S 

-2C«<-eoa7X /J 2 95 

2C4« flOSHY £22 « 

IC l6lC-eQ57M £14 50 

1C 32K aGS9C £21 2S 

1C l6<-t05lF £14 60 

ic leK eo53H £i4w 

1C 16K eaSM £14 50 
IC 1^ BG04e £14 50 
3C.32K-6C04C £«995 
10 24K KB24t £27 50 



10 32K Vl:I9M£1I995 



F.l# .1 2 

Grai>rT u 
St«i>iiici 

• B<t>i Bu»irvr$» 
Aifvintvr* C»ift»» 

GAt^titf 1rjMl*fi 

•G4llK> 

• R««<i#« Ai Higir) 
*04;r«t<M>ct <^ Rvri 
*StM Waftior 

•IwiMo^n Ori«n 

•Pi jr*: Mf'icf* 

StAt r^hi 
•JOU«i*«> To The Ptii^rlt 

M.»)i«n Aitfro*0 



10 32K aOfl9N £75 00 
tC 32IC BGOej £14 50 
10 4aK BGlOt £33 S7 
10 40K eG59^ £75 00 
2C 1W YG5I« £14 95 
IC 15K VG52G £14 95 
IC IW eOftlJV/ £T4 95 
IC 32K fiCilM £10 59 



IC 32K S0140 
IC 37< Ka25C 
1C16K 60755 
:C 32K 602 IX 
IC 32K eQ22v 
-IC 32K fl024g 
IC 33K BO^SD 
tC 24K 6Q23A 

IC 48H «e2eo 

IC 24K 8G69VV 
10 '^OK SG2eO 
IC 32K «:e28c 
IC 32K 6083 £ 

10 4ctf eooiy 
10 40* *j(i25<: 

20 40* «»2A 



£1450 
£14 50 
£14 95 

£20 n 

£1380 
£27 45 
£14 95 
£17 25 
£2195 
£11 95 
£14 95 
£2045 
£20 75 
£17 19 
£21 79 

£20 e4 



Of Coo<kc0«- * Cav^'n 
Em«c« fro<nVwVan%iyv 

All a«bi & TrM 40 Tnt«^«« 
• temptv 01 Ap*h»i (P4r r 1 » 

•Curv* Of fi« (P»'t 3t 

Crvpl Of rhf Un4f4d 
« IrrifMf • OH h* Ove#fr inC 

K1A9 Armv » Hm 
«t0r4^ 0* Mf rn^ 

Analog A^fvFOlur* 
A<fy«A[urf> L*i^ 
f trlMr Al}v«^lUUf * 
Mitfion imcoipa^ 
Voc<)MC«Mk> 

Sf f «*V9» Otfy%9«v 
MvMery f wn moui^ 

Pyramia Of Doom 
Grt»ii Towfl 
Sav*9c i»i*Ad I 
Say»9« Ui*'Hl It 



10 4aK K904t £21 95 

10 40it iteac** £20 ?5 

10 32k; B094C £29 95 
10 32< 8Q95D £29 95 
10 32K KSSU £29 95 
l0 32Ke078iCf2S93 
IC 32H 8085C £27 45 
IC 37K BOBTU £1390 
IC 3JK BQa9^V £13 90 
10 40« K832K £20 75 
'lO-40fC ><a33k £20 75 
IC 40K BG730 £2i 95 
-ID 40C KS34M £20 75 
IG 40IC eG79l £149S 
10 40* »ce350 £20 75 
10 32K B033*- £16^ 
IC 24K 8OO0A £17 9S 
IC 24K eOOlft £17 95 
IC 24K BO02C £17 95 
IC 24IC*e0030 £17 9* 
tC 24K eOO*E £17 95 
IC 24K aOOSF £1796 
IC 24K BOO^ £179S 
tC 24X B007H £17 95 
•IC 24K aOOej £17 95 
-IC 24K eO09K £17 9S 
-IC 24< eOlOt £17 95 



G^h^rn v«nr«9« 
Trt«»tir« Qut«t 

StarcfOft 
EftffgV Ct*r 

${k«w $»« uttltr MoAtit I 

Th« S^4«tf r«<} ABk4«K« 

*Th« B^nie or Sh4o»t 

*OnM«||«r Htvrr Ltrtv 

*TlfiJii[JCt 

*Hit\ Alia rate C««iivov Ratdet 

• Battle Fo* Nw-mani^ 

Wat 

• i1 NuctM' Soorib** 

•Conf'-et 2500 

• C»tfOnM#VI»ri. 

A read* Qa«n*t 
Star FUidfi 
ChopriiM* 



.1C'24K BOMM 
IC 1C«t >t«3«P 
10 40K 60938 
20 32K e096E 

-10 32K-K937S 
IC ICK VG53H 
-IC 8K V655H 

to 32K eowv 

-l0 48K-609eG 
-tC-iex KMOA 
1C-4CK.WSWT 
IC 4e9C BG7tK 
IC 24t-eG93B 
-ICieiC aG83€ 

IC 32K ooaic 

IC 37< iC83SR 
IC 4C^-KaOT6 
.10-32K-iCD40t 
-iClClC eG6«Y 
'IC 1^ 8G97U 
iC-321C-8G«5G 
1C-32K KM1U 



£1795 
£1095 
£20 $4 
£37 35 
£29 95 
£14 95 
£14 95 
£18 96 

£2895 
£2595 
£28 95 
£18 95 
£1795 
£11 95 
£1*95 
£28 95 
£23 95 
£17 95 
£1195 
f1l9S 
£1195 
£78 05 



-II eK-¥G«W £29 95 
.lO'48K.tC8l2M £27 50 



12 YOUR COMPUTER. MARCH 1983 



UACItO A$5£MtUR 



RfflRSS 



ENERGY CZAR 





ATARI SOFTWARE continued | 


Eri'^l^ao 


IE W K64a%V £29 95 


• G j'TfW^U 


ic jcit eoiau £U^ 


CMtffif 04 M«f« 


ID 16K 606^ £2995 


• ftfv*t u 


it 16K eai$V£l4 95 


KSi*fPAird 


te fcK eGszG n^ds 


•Acqwre 


IC HK SG<^V/£14 95 


*Pf£>t*tt*Jf 


IC 32X eG24B £27 SO 


•&^o£tv&8or^ 


IC 32H BG91V £U95 


*$B*e« Chi%>f 


-ic.i«K flC4av £10 as 


D tOjtfe & Domtr^tcs 


IC S6K 6043V/ ri4 95 


Gc*f 


li-UKK$**X £29 95 


♦ Pc**' S<;4i(^# 


IC 16K eQIJT£l4 95 


Andforriinia 


-ID 24K KeiTT f?2 50 


e>^iH<^ 


IC e< YG62S £14 95 


ec«-t>t< Attack 


1C 1$»C BG7DM iU9S 


Hang iTM'^ 


IC 8K yG54J £14 95 


AUeroiCs 


leetcyceoo £79 95 


WwdfJC* 


T0 32K HLW^ £19 6S 


*S:el(if SfHtitte 


-K'lW ite45r £73 50 


Wwdr«c« |P*ft 21 


lD32»<;nei0t £15«* 


*ftic<>lr%S9iK*« 


<1<M6*! BQ3SQ£M9& 


A^u»# 


i0 4o«c »:enM£^9 6S 


M.%wi» Co«»"^#^ 


11 eJt VGMU £2&9S 


Si^M'f Ct^Cwt & Titi 


IC IW &Q4aC £?4 95 


$p4<w ifiv»dc'» 


U W YG70M £29 35 


Hu(T^pt> Oo«r^T J*<* A Jn 


IC l«KeOM« £14 95 


Driut* lnv#<l«i 


10.16K tlGa4M £J*>5 


H<U>^ D't^ofy & B»4 8a* 


IC 1«K BQ39N £14 95 


K r*tvK'i^fCfk 


ir «K BGSif £29^5 


8fiit%H HvfiUQv Jiq^mn 


2C leK 60401 £14 95 


• «♦*» Guard 


iC-t^K Ke47e ft450 


t urofW*»nS<#fi# J^-w^v* 


2C 16K e04IU£i4 95 


*Sl^c*oot Ai OK a»i*vr 


TC 1*K eG9?f £14 9!f 


VK3«t> £«Krl 


M e< ftO?2P£24 95 




• IC ICK Ka4S0 £1550 


M<roP«iPl*i' 


1D4B< BG55k £27 5C 


•^OCfcCf ftlNltf S 


.1C-24K «B5lf £18 50 


P»tr>t 


10 4Blt IC932V £2995 


•Strsm 


aC'tfiK-PCeajH £24^ 


Muiic Co^i^dic* 


lt^< VG4SC £35 96 


•G*l*et>c C^*w 


-1C IWt BQ©2S £16 95 


Niovr 1 he f 11*4 


IC BK BQ34M £9 95 


r^r««h(>u 


ID.4CIC:(IG19U f27 S4 






•SpKv G A^«t <3 Pro^r^mti 


lC32»tKaSSlt£1795 


C<mtpwT«« U*9o#o«« 




*Uam LAn«S«f 


IC UK eQl«S n095 


A^-imrrt^i 


IC ISX tL32K £2195 


•N*ut4u» 


IC 32»t K6»3P £27 50 


Syn AvvwnblK 


1D4e< xe83€ £39 95 


S«4bk 


t0.4»C.<e^7W£23 50 


AwtHn|>le* Editof 


vt dK YG<J«r £39 95 


•Se« Of*9oA 


IC 1«K K$58.V£24 95 


M^K^o Au»iirkOl#f 


10 32K B073Q £5995 


^'f *1Y St»oo< Om) 


U Bit 60«3T £29 95 


B«i»t A* & Op $i^I«mA> 


•.D4fiK e032K £5995 


•$ii«mv» 


\C 16KX820W £27 50 


J^.<rotoh 8jn< 


■D 3?K eQ74R f«,995 


$«ff»rntin« 


'Ue< KB«0O«3 50 


fi»*Qi l£AXK-«icf) i€ & 2C 16K 8075$ ftf99S 1 


Ccrtpn]* 


It'lM B070M £2995 


Pilot iC0A4U«'^» 


IE eiC yG«9A £59 95 


Af^> V^tn% 


1C-«K ftGSOf £10 95 


OS Pofir. 


ID 24X Yt29G £*2 95 


•BufOn* 


iCUK.KBem £21 95 


T»r.vC 


•.D48X 8G«2$ £67 80 i 


•Dvg Attack 


1C 24IC BG36P £23 95 


tnur tftp -6$ 


10 4«K 8G«1H £9900 


• Twtt. f "uU* 


-t0o«K KM3t £1795 






•Gf ftttie Onlf 


IC 16K KB6&V £23 50 


iltititi«« 




*P*«4rK: Oo«»t Highway 

ApfritPjfW: 

T'«A Aumk 


1C 1IK 9G38R £19 95 

VI lfiK.KB«7x £33 95 

-1C IftK &G27C £27 50 

-1C.15K flG*4X £23 50 

tC 16K KB68Y £22 95 

1C 1^ Ka07H £21*5 

1C I6K aGt3** f23 50 

n 4K K%rQM £27 95 

ID 32K XfiOOG £23 50 

ID 32< <BD5F £23 50 

IE ft<C B071N £^9 95 

-1C 1« 0<W4V £1995 

.IC letC ftGiTT £2064 

10 32K BQ77J £22 95 


SAM iSp#«<A $irt>lh«s(»«f» 

Pfopr jm-vtofl AhS* Pjclt 

• 6502 OvM^w-nblrf 
Attn Wofkf 

The N«)»i St*9 
KOOS 

Ot(k M«nifi«f 
OitJi 0«tf<ifvf 
MAjC65*OpSw«i"A* 

Tftl«1ir>k 


10 32IC <B1&R (47 19 
IC tOK BG600 £t09S 

IC 16K K6e4f £74 95 
TC e< V130W £995 
10 4{K S027£ £47 95 
!C 40^ B029G £3195 
10 32< 6C.64U £27 54 
TD 32^ BO/fiM £5995 

ID 32K Kftder £1796 
'D 32K BGSflN £27 50 
10 lex 8C57M £23 50 
T032H B030H £5995 
IE %K YGSJP £2195 


K.f«^ aaia^ 


n $K ItBlfiS £?S^5 


•o^a NTfu^ni «/«^ «tiit;#fr^ iam^ ^i(« *t*a m 


P«thr.f^4«f 


10 3?K BG33L £20 «i 


m*fT*o*r t*tf i**9f t* 4tt**fri\f 1 


*Ubvr*^m 


IC ISK <S71N £23 50 




1 


•Cro«»fire 


IC I6X SG22V £2064 


Soc^t 


1 


TumM*8tf^ 


10 24i; fiC46A £23 50 


M«s«cf Mcrr^v Map 


'XHbJU £4 00 1 


Wi/dcdOfWM 


to 32K Xfi03D £2995 


De fl* Aian 


wGseifieas 1 


• Tt-fy Bomti 


-1C-H< eG40T £1095 


004^4tifV9 S>^i«m Ui«f't M«riiuti 1 




IC UK b03?$ £1095 


^ Hjf (jwaff M»*iwat 


-VM46A£ie95 1 


lTB»eef 


-IC 16K H873Q £19 95 


Al4<iB^licU«rrtfr>9erUl4no V^SSK £5 24 1 


«(kw$#«R*c«* 


IC leK 8G29C £3750 


G»ti«s F««' T^e Alan 


'WA^7B £4 45 1 


«M4tchf«c«^ 


-IC Utt 66JHJ £22 50 


AlMi %9%K 


-VVCOS^ £6 BO 1 




IC 16K KB74« £22 95 
*1C t6K <876H £21 SO 
.IC-1«X 8G99H £1195 


Aiari Sourtd & Cr4ph<* 
Your Al*rj Compu;«f 


-WA39N £8 25 1 
WA40T £13 45 1 


•Sfw<rtK%90»l>*rr 


IC l«>t B036I'I14 95 


6502 AsMmblv laf>9u#9* $utK0^1i»tS | 


*Shixrii<^A;c#<}« 


-1C leic BGISn £2350 




•WAOSf" f 12 45 I 


fl«»t«ftll*M»f 


10 32IC 8G350 £22 95 


A«K*f>c#d 6S0J i«Mi*fiti*>9 


WA41U nt 45 1 


Dai^» M<«n*oNt W«o»e 


-l0 48JCHft?$lC £27 50 


0tv<Hid G«me» (65021 


WA^SYflSOO 1 


Su»* B4t»Mni1 


tf ZK XQHtX £24 95 


C«mpitt«ft Fc* P*cpt« 


VVAOOA £6 25 1 


•ChMm A a*mKAi. 


IC 16K l^87X £23 50 


Ana^ Trt« M^*4tr%« For Aun 1 


Gu^i Of f 0*1 VH**r€» 


4C3aK-ilG7«K £14 95 


t€ .»u#f > Art«a*l $ub*<*.oiK>rt G624S £900 1 


Moum«i<*iSn<w) 


IC IdK d0l2N £1095 




I 


•TaM rf»p 


TC !$)( YL34M £8 95 




1 








Kcm« E4tf«f i»rtm«iu 






Scf*m 


1C.16K YG5«N £1995 


Ofd«f At XH&2G - ltM« 3 1 


KrHKlovl 


IC 1«X <«81C £14 95 


Kwi: C - Casteti* Dt»k 


E CftfirKMift 1 




IE 8iC VG6IR £24 95 
1C-16K B020VV £39 50 


2C 2 C*ii«tttti etc m. t$K show» (ntmnnom 1 


Siin««T Got* 


tC 16K B015P £10 95 
IC 1«>C KM20 £17 19 


rrtftitiofy fM]utf4BiTvcni 


1 


Gof 0«n«r,^ 






T«urA«^*rtl & B 8»1tPoo< 


IC 1«K 8045Vfl9 95 


Note OfCtef codes shown in brackets. | 




IC 1EK 9G478 £1380 
ti 9irQ63X £24 95 


Prices correct at time of going to press, 1 


*JM G»ffl".^ 


*C %K nm £1695 


(EffOfS excluded) 


II 






■ 



mm 

THE NEW 

MAPSOFT CATALOGUE 

48 full colour pages of Atari, Dragon 
and VIC 20 hardware and software. 
A comprehensive guide to what's ^ 
available. Price £1., 

THE NEW 

MAPLIN CATALOGUE 

contains full details of all the 
computers and most of the software 
shown here and much more. On 
sale now in all branches of W.H. 
Smith price f 1 .25. Or send £1 .50 to 
P.O. Box 3, Rayleigh, Essex. 




VIC20 COLOUR COMPUTER 




Hardware 






SxmplKaic Ca»««tle (>16K) 


*AC938i 


£19 95 




viao Comott 


(AM7B» £169 99 


VIC Slock Control Cass«tt« i*%Ki iAC94Ci 


£1995 




C2N C*v*eTte Unit 


^Am 


f44 95 


VIC file D4k(«T6K» 


tAC«Ol 


£24 95 




VIC Pnrti»r 


(AF490I f 230 00 


VIC Wr.ier Oi*k <*8X| 


*AC9«€| 


£24 9S 




V»C Of*^ Onv« 


(AFSOCi £39«00 


V*C Wntef C«B«ne ,*e!<l 


(AC97F; 


£19 95 




3K BAW C»*tf.09« 


lAfSIFj 


£2995 


SdMatiOf^ (CS£ tt GCE 0' L«v«l AcvHS^Off} 






m BAM C»ftf.d9© 


(Af§2G) 


£44 95 






l^kftAMC^ftrid^* 


tAFS3MI 


£74 95 










J»>«lfcli» and Paddt«« 






Engirt K Lafi9us9« 


(AC«eC| 


£«»9 




Pan of Jcvsttdis 


tAC53M} 
(AC37SJ 


£7 50 
£13 9& 


M«h*fnstK» 1 


tACWHl 
<llCOOAl 


£9 98 
£999 




L«S!NA 

Pair 01 PMl4&e» 


(AC45VI 
tAC30H* 


£24 95 
ri3d5 


8io<09y 

ChamiMfv 

Pttyne* 


iGcoiei 

I8C02CI 

(ecoaoi 


£999 
£9 99 
£9 99 




Pr09r«mnning A«d C«itrido«« 






CtiffpoiH Stu0ia« 


tSCOAEl 


£9 99 




Su0«* E*pjiod«jf ZK RAM *rt<l Ht res 




Caogrtotiy 


<GCOsr» 


£9 99 




^rapnw:* 


(AC54J) 


£34^ 


Kt*lO*V 


<eco«Gt 


£9 99 




Pro^tf jnmiif^ Am3 AtKttiOfiil cammartd*. 




Artthmaiic (c 9 to n >a*f oWt 


teco7H. 


£9 99 




fi^itctKifi Krr iyoa'4*^"^"*^ PTC {ACSSKi 


£34 9^ 


RtjArtfl tof 9 to n V9it o<is$ 


(SCO&IJ 


£999 




Ma<bii*<j Co<l* MomiOf 


(ACS&J 


/34 95 
















(&C09K) 


£9 99 




Software (at) 3K unlast ttatad) 




Sj>«llir.9 le* 9 10 1 1 i*ar oidi 


leciOLj 


£9 99 




Iniroducttor) TO BASIC Cmmii«» 




Hama Pro9rMni 








P*a » 


tAC57M) 


£14 95 


An cas^ttp b**eO «no f eouirii^ a 


1 kasi 8IC ejio^nirort 1 




^»n J 


(AC&eWl 


£14 95 


mi^nory 








Gwnft Programs 






Oif«|rr«f;er 


(BCIIMI 


£9 99 




Av?ir>9ef CBfiri<H}« 


(AC5*P) 


£1995 


KfHiW You* Otf»n »Q 


.&C12NI 


£9 99 




STuf BmW^ C»'irHf9« 


(AC60Q) 


£19 95 


Jt^nio* IQ 


tBCl3»» 


£999 




Sup*^ St04 C4(ir>dg« 


(ACCIRI 


fl9 95 


Koow Your Own P**so<t»>,i^ 


leCUQi 


£9 99 




J*lt^ Motv*cef > C«r(r*<3;e 


iAC$7$i 


a^9b 


Tl^a Ro6err Camer f imil^ M#nv piann^r 






Al)«n CA'iri<Jfle 


tACe^I) 


a^ss 




iBCISfl. 


£9 99 




StfWfr Larxitff CifirM)^ 


(AC*4U> 


£i»96 


VIC Mornry Mirajt* 


!9C16S^ 


£9 99 




Ro*d R»c* C»ttrid9t 


CAC65V) 


fld9S 


VIC Road Ut*' & H.«h*^*> Co(»> 


tOCt7T; 


£9 99 




Rat Rjjce C,iMftdQ4» 


lAceevi-j 


fiass 


Gafdei Planner 


ieci8ui 


£9 99 




ehti C^swnc 


(AC67X) 


£4n 


trie<tOf Oa*-gn*' 


|8C19V» 


£9 99 




Molt AUMk C4«ir><39e 


fACiSGI 


£24« 


BaC A»i^ Tha Famiv 


I0c^c^vl 


£9 99 




AitvoMuf«l**yj Caiir>d9e 


(ACMII 


£24 95 


dfiC M«»i#«fn»'^ 


ieC21X! 


£9 99 




Ptfai« Cove C«rlri4f|« 


(ACaaF) 


£24 95 


M«Te'm*f><I aodft-ci^al C*rtr*<i K«aA»eog 


r 




Mat>o«i impcisiblf C^^ftdge 


fAC87U* 


£24 95 


D4ta 1 


(ec22ri 


£2 50 




VocMloo C»*ii» Carif Kf$« 


(AC«SV) 


£24 95 


Oau2 


<8C23A| 


£2 50 




Tfi«! CouM C«rtf«<^e 


tAC«9Wj 


£24 95 


0414 3 


ieC24Si 


£2 50 




Sft'Qon 2 Ch#t» dnrto^o 


tAC77JJ 


£74 95 


Omua 


[BC25CI 


£2 50 




Gorf CattfiD^e 


eAC90XJ 


£24 95 






On-aji RaceCart(itf9e 


iAC9lVl 


r24 95 


W-n* Ci Food 


mcim 


£2 SO 




Anochaf ViC m Th* W«i( Ca^tette 




Mu»ic 


m2m 


£2 50 






{AC78K> 


£7 00 


SaofT & G»«ti#i 


teC28F| 


£2 60 




VJC Paftic Cats«ite 


lACTSCi 


£700 


F.T'n^ft TV 


i&C29C} 


£2 60 




Coirrtfadi Cau4'tte 


lACSOej 


£700 










eaa^amnwi Cafseiit f*3Kl 


[ACftJO 


£7 00 


eoofct AbOMl VIC 








VK Man CaiMrtl« 


(Acezo) 


£7 00 


L**'r> Projrammir^ on me VJC 


(W'A3Ui 


£2 50 




VIC AWtrOKii CatMtttf 


(AC83e» 


£700 


VIC Rrvcaresl 

VIC PfOQtarnmM* Ai^tf a/T<« 


(WA3a't» 


£1000 




euttfieti Program* 






Gi^)0» 


{WA33L1 


£9 95 




SjrTiDiiCJ>^-0.|A<*1filCl 


<AC92A) 


£24 9$ 


V»C Graflh.c* 


(WA48C^ 


£1000 




Lots Of iww VIC20 softwaro now ovailablo 









Maplin Electronic Supplies Ltd., P.O. Box 3, Rayleigh, 
Essex. Tel: Southend (0702) 55291 1 /5541 55. 

Demonstrations st our shops NOW. See the computers in action at 
159-161 King St., Hammersmith W6. Tel: 01*748 0926 
284 Loncjon Road, Westcliff-onSea. Essex. Tel: {0702) 554000 
Lynton Square. Perry Barr, Birmingham: Tel: (021) 366 7292. 



YOUR COMPUTER, MARCH 1983 13 



DEMUfRESAe 





From now on, you won't have to took tar tor a totally professional home computer dealer. 

Just look tor the name that says It all. COMPUTERS FOR ALL 

It's the newest and most exciting network of Micro dealers in the U.K. 

The ideal places to buy, browse, seek advice and after-sales 

service . . . professional service! 

Every COMPUTERS FOR ALL dealer is dedicated to giving you, the customer, 

exactly what you have always wanted ... a shop or store that knows about computers, 

capable of helping you sort out what's right for your needs; expertise 

In giving sound advice, knowledgeable in technical matters. 

If you've ever bought from the usual retailer who just stocks and sells, 

you'll appreciate the difference! 

A COMPUTERS FOR ALL dealer Is a shop where people matter . . . why not 

call in at your local one today. You'll get a friendly welcome! 



14 YOUR COMPUTER, MARCH 1983 





FRIENDLY SERVICE AND THE WORLD'S FINEST MICROS! 

You'll find a wide range of popular Micros at a COMPUTERS FOR ALL dealer 
Atari 400 and 800, DRAGON 32, Commodore 64, Oric I (48K) and 
BBC Micro to name a just few! Plus of course, the sort of dealer 
who can (and will) explain which 
one is best for your needs! 

HARDWARE, SOFTWARE TOO! 

A COMPUTERS FOR ALL dealer also stocks a great deal of the very best hardware 

and software, so that you can expand Into new worlds of computing. 

Everything from equipment like EPSON and SEIKOSHA printers to a fantastic new range 

of ATARI software direct from the U.S.A.! 

Of course, you'll also find lots of other items of interest at a COMPUTERS FOR ALL dealer. 

Books, BBC Software, DRAGON 32 Software 

the list is endless! 

Call now at your local shop or store. 

Look for the name that says it all . . . 

COMPUTERS FOR ALL 





Where to find your COMPUTERS FOR ALL DEALER 



ANIROG COMPUTERS 

26 Balcombe Gardens 

Horley. Surrey 01-648 3471 

BITS & BYTES 

44 Fore Street 

ilfracombe, Devon 

0271-62801 

CARLTON COMPUTERS 

4 Swanstons Road 

Great Yarmouth, Norfolk 

0493-58898 

COMPUTASOLVE 

8 Central Parade 

St. Marks Hill 

Surbiton, Surrey 

01-390 5135 

COMPUTER CORNER 

c/o The Wickford Video Co. 

15 The Broadway 

Wickford, Essex 

03744-3710 

COMPUTER SYSTEMS 

(TORBAY) 

Pump Street, Brixham, Devon 

08045-6565/6 



COMPUTERS FOR ALL 

72 North Street 

Romford, Essex 

0708-752862 (two lines) 

CRYSTAL COMPUTERS 

209 Union Street 

Torquay, Devon 

0803-22699 

DAN EVANS (BARRY) LTD. 

81 Holton Road 

Barry, South Glamorgan 

0446-734242 

EMPRtSELTD. 

58 East street 

Colchester, Essex 

0206-870353 

EMPRISE LTD. 

3a Baddow Road 

Chelmsford. Essex 

0245-356834 

KENNETH WARD 

COMPUTERS 

KF&R Mouse, London Road, 

Ascot, Berkshire 

0990-22275 



D.V.MARTIN LTD. 

13 Bridge Street 
Belfast, N.Ireland 
0232-226434 
MEDWAY COMPUTERS 
141 New Road 
Chatham, Kent 
0634-826080 
MERCATOR COMPUTER 
SYSTEMS 
SWhiteladiesRoad 
Clifton, Bristol 
0272-731079 
MOBILE MICROS 
2 Castle Street 
Thombury, Bristol 
0454-418383 



STEVE'S COMPUTER CO.LTD. 

Castle Arcade 

Cardiff, South Glamorgan 

0222-41905 

TWILLSTAR COMPUTERS 

17 Regina Road 

Southall, Middlesex 

01-5745271 

WEYTECH COMPUTER 

SYSTEMS DIVISION 

20 St. Edmunds Street 

Weymouth, Dorset 03057-79881 

KELLY'S 

COMPUTERMARKET 

227 Dartmouth Road 

Sydenham, London SE264QY 

01-6994399/6202 




COMPUTERS 




'THE SHOP WHERE PEOPLE MATTER ' 



YOUR COMPUTER. MARCH 1 983 15 



ANIROG SOFTWARE 



KRAZYKONG 16KVIC20 

All the thrills of the arcade game have been brought to life 
on this expanded screen, extra large characters and multi- 
screen presentation. Rolling barrels, hammer etc. are 
featured in the action inside King Dong's lair as you try to 
rescue the boy he has abducted. K. B . / J . S. £6. 

ZOK'S KINGDOM 16K VIC 20 

An afternoon stroll turns into a nightmare. A footslip and 
you fall down the biztual hole leading to the middle earth 
kingdom of ZOK, A harsh and cunning ruler by any 
standards- You are challenged to a battle of wits and 
endurance as the battle for survival starts in earnest. 

K.B.E6 

DRACULA 3KVIC20 

Count Dracula is asleep somewhere in his castle. He rises at 
mid-night and you must find him and drive a stake through 
his heart before he rises. A multi-screen graphic adventure. 

K.B.£6. 

HOPPER 16/48K SPECTRUM 

SPECTRUM version of FROGGER with same features and 
brilliant graphics. K.B. £6. 

PHARAOH'S TOMB 16K VIC 20 

A graphical adventure game set in a pyramid. Once you 
enter, the only way out is with the aid of a key which 
unlocks the mystery of the Pharao's tomb. Beware of the 
mantraps the ancient Egyptians so painstakingly built. One 
false move and you will meet the same fate as befell other 
tomb robbers over thousands of years. 



FROGGER UIMEXP. VIC 20 

Popular arcade game. All machine code with brilliant colour 
graphics and sound effect. Features include snakes, 
crocodiles, lady frogs, turtles, cars, lorries and logs 

K.B./J.S,£6 

CAVERN FIGHTER UNEXP. VIC 20 

All M/C version of SCRAMBLE. Lasers, bombs, 
continuous scoring and sound effects give all the thrills of 
arcade game. Pilot your space ship through the tortuous 
tunnels and caverns destroying enemy missile launchers, 
fuel dumps and airborne fire saucers. Four ships to 
complete mission. 10 skill levefs. K.B./J.S. £6 

CRAWLER UNEXP, VIC 20 

Armed with a laser gun, you must destroy the centipede. 
Destroy his mushroom cover and his allies mushroom 
laying flea and the homing spider. Fast and furious game. 

J,S.£6. 

SEVEN PROGRAMS(VOLI) UNEXP. VIC20 

This exciting collection of seven games, all in Hi-Res 
graphics include popular board game Othello plus Bomber, 
Slalom, Bounce Out, Snake, Memory and Lunar Docker, 

K.B. £6. 

SEVEN PR0GRAMS{V0L2) UNEXP. VIC20 

This pack with all games in Hi-Res graphics contains 
graphical adventure game Goblin's Gold plus Ghosts, 
Breakout, Dare Devil, Minefiled, Grand Prix and Cobra. 

K.B. £6. 

TINY TOTS SEVEN UNEXP. VIC 20 

Seven games for young children. All games are in Hi- Res 
graphics with bright graphics. The games include Super 
Snap, Simon, Bombs Away, Noughts and crosses. Duck 
Shoot, Mad Drivers and Santa, K.B. £6 




GENEROUS DEALERS DISCOUNT AVAILABLE 
AREA AGENCIES AVAILABLE. 

SOFTWARE WRITERS 

We are looking for top class writers to join our growing software 
team. If you have written a quality game for VIC 20, SPECTRUM, 
DRAGON 32, ORIC 1 or COMMODORE 64, then contact us. We pay 
top royalties for accepted programmes. 



ANIROG AT CO-OP CRAWLEY 



Huge selection of software and Computer Books for 

SPECTRUM - ZX81 - VIC 20 - DRAGON 32 - 

COMMODORE 64 

Most of the software and add-on's advertised in this magazine for 

these computers available across the counter. 

Manufacturer's appointed dealers for DRAGON 32 - VIC 20 - 

COMMODORE 64 and ORIC home computers. We stock full 

range of peripherals (disc drives, printers and memory expansions) 

and support software. Come and see us for expert advice and 

comprehensive service. 



m 



MAILORDER 
ANIROG COMPUTERS 
26 BALCOMBE GARDENS 
HORLEY SURREY 



rA^^^»~ 



MJ:yn!.j 



5^5 



VISA 



Payment By Cheque/ 

P.O. /Access or Visa 

CREDIT CARD SALES 

HORLEY (029 34) 6083,' 2007 



r 6 YOUR COMPUTER, MARCH 1 983 



MICRO 
INSTANT 
MACHINE 
CODE! 

Yes, it's true. Instant machine code fronn a good 
subset of BBC BASIC Type your BASIC progran\ 
into your nnodel B BBC Micro, trigger the 
connpiler, and your program is changed almost 
instantaneously into superfast machine code. 
For £34.95 you get; Cassette version of the 
complete compiler (along with a version of the 
compiler for use with discs, ready for when you 
upgrade, the disc version being dubbed on the 
cassette after the cassette version); complete 
compiler listing; extensive documentation and 
instructions. The compiler was written by Jeremy 
Ruston. 

THE BBC MICRO 
REVEALED 

By Jeremy Ruston 

'. , .destined to become the bible of ad BBC microcomputer 
users. . .'{Personal Computing TodayKlfyou've mastered the 
manual, then this book is for you. Just £7,95 

LET YOUR BBC MICRO TEACH YOU TO 
PROGRAM 

By Tim Hartnell 

'. . .takes you further into the cloudy areas of the BBC machine 
than anything e(se I've yet seen. . / (Computer and Video 
Games). If youVe just starting out in the world of programm- 
ing, then this book is the one for you. Forty complete 
programs, including Othello/Reversi, Piano and a host of 
dramatic graphic demos. Just £6.45 



Interface, Dept.YC 

44^46 Earis Court Road, London W8 6EJ 
Ptease s«nd me: 

( ) INSTANT BBC MACHINE CODE -tape and book-£34.S5 

( ) THE BBC MICRO REVEALED- Ruston -£7.95 

t ) LET YOUR BBC MICRO TEACH YOU TO PROGRAM - 
Hartne)f-£6.45 

I enclose £ 



Name 



Address 



SPECTRUM 






■-^ 




im 



Make the most of your Spectrum, with these 
acclaimed books from the experts! 

PROGRAMMING YOUR 
ZX SPECTRUM 

Tim Hartnell and Dilwyn Jones 



More than 100 routines and programs, 230 pages, and value 
for every Spectrum user. Learn how to make the most of 
user-defined graphics (with a Pacman-like program, 
DOTMAN), sound, colour, and such commands as ATTR; 
SCREENS and BRIGHT. From the co-ordinator of the National 
ZX Users' Club, Tim Hartnell. Just £6.95. 



THE SPECTRUM 
SOFTWARE LIBRARY 

60 GAMES AND APPLICATIONS FOR THE 
ZX SPECTRUiMt 

By David Harwood 



Arcade games, intelligent board games, brain games and 
utility programs. They're all here in this massive collection of 
60 tested programs for the Spectrum, compiled by interface 
columnist David Harwood. Just £4.95. 



Interface, 
Dept.,YC 

44-46 Earls Court Road, London, W8 6EJ 
Please send me: 

( I PROGRAMMING YOUR 2X SPECTRUM -£6.95 

I } THE SPECTRUM SOFTWARE LIBRARY-£4.95 

( ) A sample issue of INTERFACE, the monthly magazine 
published by the National ZX Users' Club-£l-00 

I enclose £ 

Name ., „..„..„.„ 

Address ..., 



YOUR COMPUTER, MARCH t983 1 7 




Vic20 5k £137.95 21k £177.90 

includes 5 Free programmes. 

VIC Cassette £44.00 VIC 1 541 Disk Drive £299.95 
VlCPrinter £229.00 NEW 16K RAM Pack £39.95 
f^f^ff^ Ideaf for Commodore computers 

Ifc^*^ Selkosha GPlOO VC Printer £239.95 
Commodore 64 Software Now in Stock 

Main Commoclore Dealer 

#QI^« New 500 series. New 700 series 

M%0M m Business Computers. 



Basic Cartridge £34.90 
48k Up Grade for Atari 400 £73-50 
Atari 800 1 6K inc Atari 4 1 Cassette £49.00 

basic £399.00 Atari 810 Disk 

Atari 800 48K inc Drive £299.00 

basic £469.95 Atari 822 Printer £199.95 



I2I3S1 



Plus Daisy Wheel and Dot iVIatrix printers 
for the Atari range. 



Atari 400 Typewriter keyboard. Direa easy 
replacement for standard keyboard £78.95 



New Vic Software 
Krazy Kangf 

Dodge Kong's barren's as you 

climb the stairs. 

STDVfC, Joysticks. £6.99 

Extermlnatorl 

Blast the centipede while 

dodging the spider amongst the 

toadstools. Fast action. 

STDVfC. Joysticks £6.99 

Antl-spfatter-matterl 

Make space invaders look like 

chifds pfay, superb graphics. 

STD VIC. Joysticks. £6.99 

Vlkman 

Choose one to three ghosts. 

STD VIC. Joysticks £6.99 



3-D Man 

BriUiantl You are down in the 
maze like a Pac-Man. dodge the 
ghosts and find your way outi 
Expanded VIC Joystick £9«95 
Motorway Maniac 
Accelerate towards on-coming 
traffic while dodging from lane 
to lanel 

Expanded VIC Joystick £9.95 
Defender on TrI 
Guide your ship through the 
maze on 4 different screens. 
Fantastic colour and graphics. 
Expanded VIC Joystick £9.95 

»00's of other programs. 
Send for VIC price List. 



Largest Stocks of Software in South London. 
Available on Cassette, Disk or Cartridge. Massive 
ranges for: 
Atari, Spectrum, ZX81, BBC and Dragon. 



Printers 

We carry a wide range of printers incfuding: 
Amber Dot Matrix £89.95 

Seikosha GP 1 OOA £2 29.95 

Epson MX80FT3 £389.95 

Smith-Corona Daisy Wheel £549.95 

Cables and interfaces for most home 
micro's in stoclc. 



THE AMAZING ORIC - 1 

Colour Computer 

^ * 40 Columns x 28 rows. 
* Microsoft Basic 
it 8 Colours. 
* Built-in Sound 
Synthesiser. 
* High Res Graphics. 

48K Microsoft Basic £169.95 
1 6K Microsoft Basic Phonel 
Come In for a Demonstration. 




Sinclair Spectrum colour computer 



I6K £123.95 
48K £173.95 

We carry massive 
stocks of Software 
for the Spectrum. 



Sinclair ZX8 1 

16KRAM 

Printer 



£49.95 
£27.95 
£59.95 




DRAGON 32 £198.95 

Limited stocks available. New software coming in 
all the time. Come in for a demo or send for our list. 



Over 900 software programmes always in stock. 
We carry probably the widest range with 
continuous demonstrations. - — ' 



Export 

All our hardware and software is available Tax- 
Free to overseas customers, please send for our 
comprehensive list. 



AM our prices Include VAT 

Mail Order — send for our comprehensive list. 



^'your old machine. 



;xchange deals or cash 



Ask 

atKJut our 

Credit 

Facilities 



Access/ 

Barclaycard 



B 



mssM 



VISION STORE 



3 Eden Walk Precinct, 
Kingston-on-Thames, Surrey. 
Tel: 01-546 8974 




18 YOUR COMPUTER, MARCH 1983 



THE IDEAL HONE 

FOR YOUR 



HOMEXONPUIER 



The System Care Desk - made specially for 

home computer systems. Designed as a neat, 

smart piece of furniture for your home. 

£49-9f 





• Supplied as a flat-pack. Easily 
assembled. Full instructions 
provided. 

• Smart teak effect finish. 

• All cables can be neatly and 
safeiy 'hidden/ 

• Ergonomically designed. 
Sliding shelf positions the 
keyboard at the right distance from 
the screen to suit you. Slides away 
after use. Saves space. 

HASreRPyiG 



• Easi-glide castors allow you to 
move your computer installation 
where you want it. 

• Houses computer, disk drive / 
cassette recorder and monitor, with 
ample space for tapes, books etc. 
Overall height - 0.83m. 
Computer sheff height - 0.70m. 
Width -0.70m. 

Depth (with shelf closed) - 0.38m. 



Exhibited at the P.C.W. Show 
and the Northern Computer Fair 

And now including design features based on our discussions with home 
computer users. Send for yours TODAY. 



• ••••««- «*•«*** *««•■■• «■ 



*•* *•• •*• •** ••• 



•**■•** 



At home with your computer. 



NOW AVAILABLE TO YOU 
BY MAIL ORDER DIRECT 
FROM THE SUPPLIER. 

Micro Aids. 2 Boston Close, 
Culcheth, Warrington. WA3 IBR 



ORDER BY FREEPOST - send the coupon or order in writing along with your cheque or postal order in an envelope 
- no stamp needed. Please allow up to 28 days for delivery. And there's a 1 4-day money back option, in the event 
that you're not fully satisfied with your purchases. 




Provides you with just one 
"owlloodingotiaamp . 




To: Micro Aids, FREEPOST, 2 Boston Close, 
Culcheth, Warrington, WAS 1BR 



n 



ORDER! 



QTY ITEM 

System Care Desk _ 

4-Way Master Plug . 



ITEM PRICE 

_ £49.95 

_ £8.95 



TOTAL 



Post/Pkg £4.95 

1 enclose a cheque/postar order payable to Micro Aids for £ F 

■ Please de^t© as appticaWe. ' 

Signature 

PLEASE PRINT 

Name: Mr/Mrs/Miss: 



Address. 



1 

1 

FREEPOST - no stamp needed. Prices apply to U.K. only. Export prices on application. I 



.Tel: 



Three out of every four 
computers going into 

schools are BBC Micros. 
Is there a lesson to be 
learned by every user? 



As part of the current government subsidised 
scheme aimed at introducing micros to schools, 
the Department oHndustry undertook a survey of 
machines available and made recommendations to 
education authorities all over the country. 

The BBC Micro met their priorities exactly: 
it is economical yet fast and powerful, and it can 
justify the investment involved, through its capa- 
bility to grow with the needs of the user and with 
the rapid changes in technology. 

Ifiachers and education authorities agreed, 
and today it represents over three-quarters of all 
micros being ordered for schools across the 
country under the DOl scheme. 

The BBCs choice too. 
In choosing a machine to put their name 
to for their massive Computer Literacy Project, 
the BBC had the same set of priorities as the DOl. 
The BBC Micro is now an integral part of that 
project, which includes books, software, courses 
and a number of major television series, one of 
which,"Making the Most of the Micro'' is now 
being broadcast 

All this for only £399. 

The BBC Micro is light and compact It 
generates high resolution colour grapliics, and is 
capable of synthesising music and speech using 
its own internal speaker. The keyboard uses a 
conventional layout and typewTiter feel. 

The most sophisticated version (called 



Model B) is available for only £399. (There is also 
a basic model available, the Model A, at £299.) 

Designed to grow: 

c* — f — p— 

Last year the magazine "Which Micro?" said 
that the most attractive and exciting feature of the 
BBC Microcomputer was its 'enormous potential 
for expansion' 

This is indeed one of the 
features that sets it aside from 
the competition. 

For example- as well as 
interface sockets to allow vou 
to connect to a cassette 
recorder, and to your own 
television, you can also use 
video monitors, disc drives, 
printers (dot matrix and 



rrrrrrt 




daisy wheel) and paddles 
for games or laboratory 
use. 

You can also plug 
in ROM cartridges con- 
taining games with 

specialist appHcation ^^■■■■■^iMWBMBi 

programs. 

The Tube. A unique feature. 
The Tube, which is unique to the BBC Micro, 
provides for the addition of a second processor via 
a high speed data channel. The possibilities are 
enormous. For example, the addition of a second 



! 



3MHz 6502 processor with 64K of RAM doubles 
processing speed. While a Z80 with 64K of RAM 
opens the door to a fully CP/M* compatible 
operating system, with all the benefits for business 
applications. 

Linking u p with other computers. 
The BBC Micro also offers a faciUty of 
immense potential value to schools, colleges and 
businesses. Its called Econet - a system which uses 
telephone cable to link uith other BBC Micros. 
A number of machines can then share the use of 
expensive disc drive and printer facilities. 

Make full use of Prestel & Teletext. 
With special adaptors vou >W11 not only be 
able to turn your TV set into a Prestel terminal and 
leietext receiver, but you can also take data and 
programs direct from these services. (The programs, 
which are known as telesoftware, are already being 
broadcast by BBCs Ceefax service.) This is another 
first for the BBC Micro. 

BASIC plus. 
A sophisticated version of BASIC has been 
chosen for the BBC Micro, which incorporates 
features normally found onlv in more advanced 
high level languages. However, there is also a facility 
allowing access through a simple command to 
another language - for example, P4SCAL, 

FOKIH and LISR Trademark of XYvpi^X Re.^arrh. 




A full range of software 
Applications software for the BBC Micro 
already cover a very wide field. Packages covering 
games, education and business applications are 
available on cassette. M\ developed to the same high 
standards set by the hardware. 



The best possible back-u p. 
Your BBC Micro comes with the backing of the 

BBC and an extensive dealer and service network. 
Each approved dealer is able to offer advice 

and carry out expansion work and repairs. 



BBC Microcomputer - Model A and Model B. 



2MHz6502A Processor. 



32K ROM: 16K RAM Model A, 32K RAM Model B. 



Full QWERTY keyboard wth 10 user-defmable 
function keys- 



Mixed high resolution graphics and upper and lower 
case text 



300 baud and 1200 baud interface for standard cassette 
recorders. 



Ihree-voice music synthesis with full envelope control 
feeding internal loudspeaker. 



Interface sockets (Model B only) - RS423, for analog 
inputs (Centronics and user port 



6502, Z80, 16032 second processors* 



Single and Dual Disc Drives with 100 and 800 K-byles 
storage. 



Teletext unit 



Speech synthesis. 



Networking facility- via Acorn Econetf^ 



How to buy your BBC Micro. 

If you are a credit card holder and would like 
tobuyaBBC MicroB,orif you would like the address 
of your nearest stockist, just phone ()l-2{)0 0200. 

Alternatively, you can buy a Model B directly 
by sending off the order form below to: BBC Micro- 
computers, c/o Vector Marketing, Denington Estate, 
^yiingborough,NWhants,NN8 2RL. 

All orders are despatched by fully insured 
courier and come complete with easy to follow^ 500 
page User Guide and Welcome cassette. 

01-200 0200 credit card holders. 



To BBC Microcomputers, c/o Vector Marketing, 
Denington Estate, Wellingborough, Northants IS N8 2RL. 

Please send me BBC Model B Micro- 
computers at £399 each, inc. VAT and delivery I enclose 
TO/cheque payable to Acorn Computers Limited 
Readers .4/C or charge my credit card. 

Card Number^ , 

\ ni ex/ 1 J i ners/ V i sa/Acccsft ( i >cteie} 

Name 



Address. 



-Postcode. 



Signature. 



YC3 



Rp^istf ri'd No. 140 3810 \ \T V 2l5 4(M)22i) 



The BBC Microcomputer System. 

Designed, produced and distributed by Acorn Computers Limited. 



Let Commodore 
expand 

yournorizons* 

VIC 20 is the finest home 
computer that money can buy. 

And the better you get to know 
it, the more confident, adventurous 
and ambitious you'll become. 

You'll want to take advantage 
of the vast range of VIC software: 
a superb and constantly-growing 
selection of programs, embracing 
business systems, entertainment, 
education and many applications 
in the home. 

Every program in the series 
has been designed by experts, and 
chosen for its quaHty and value 
for money. 

VIC business software covers 
a wide range of appHcations, includ- 
ing spread-sheet analysis, stock 
control, information handling and 
word-processing- 

A mind-blowing range of 
games including Scott Adams' 
world-famous Adventiore' series. 

Advanced space games, includ- 
ing the sophisticated 'Omega Race'. 

Learn subjects as diverse as 
EngUsh Language, programming, 
and biology 

And 'home' software ranges 
from IQ tests to Robert Carrier 
menus. 

In addition, there is a range 
of VIC software, like programmers' 
aids and graphics packages - 




to add to your understanding and 
enjoyment of computers and 
computing. 

There's even a special 'VicSoft' 
Club for VIC 20 enthusiasts, 
with many advantages including 
special offers to club members. 



.^T) 






VIC software will expand your 
horizons. And your mind. 

PRICES RANGE FROM £4.99 to £24.95 INC. VAT 

^Z cammodore 

VIC20 




I For more inf omniation, a catalogue of ViC software 

and details of your local retailers or dealers, please phone or 

complete the coupon and send to: 

The Commodore Information Centre, 

675 Ajax Avenue^ Slough, Berkshire SLl 4BG. 

Telephone: Slough (0753) 79292. 

Name 

iMRyMRSyMISS! 

Address - 



Postcode 



VQYOQQSU 



For the best hardware, 
the best software. 



The BBC Microcomputer system is 
generally regarded to be the best micro in its 
price range you can lay your hands on. So, if 
youVe thinking of buying one or already own 
one, you'll want to know about the software that's 
been specially designed for it 

Not surprisingly it's made by Acornsoft, 
the software division of Acorn Computers Ltd., 
who designed and built the BBC Microcomputer. 
So naturally you can expect the highest cpaality 
software with the built-in ingenuity to fully 
exploit the BBC Microis potential. 

Further education for everyone. 
Creative Graphics, which includes the book 
'Creative Graphics on the BBC Microcomputer' 
(price £17.45), provides 36 programs on cassette 
producing a spectacular range of pictures and 
patterns in full colour, including animated 
pictures, recursively-defined curves and three 
dimensional shapes. 

Word Sequencing (price £11.90) contains 
three word sequencing programs on cassette. 
Each program presents a series of jumbled 
words which must be arranged on screen to form 



either a proverb, nursery rhyme title or a 
sensible sentence. 

Learn more lan guages. 
LISP (price £24.35) is the fundamental 
language of artificial intelligence research. 





It consists of 5.5K of machine code interpreter, 
plus 3K of initialised LISP work-space 
containing utilities and constants. It comes 
complete with a book that introduces you to 
programming in LISP as well as some 
fascinating applications. 

FORTH (price £24.35) is a complete 
implementation of the FORTH language 
to the 1979 standard specification for the 
BBC Microcomputer Model B.This much 
acclaimed programming language is 
also accompanied by a specially 
written book explaining all you need 
to know. 

Mind-bo ggling g ames. 
Philosopher's Quest (price 
£9.95) is an advanced adventure 
in which you tell the computer 
what you want to do and it 



\ 



mrrtr 





describes back in plain English your progress 
through a fascinating world of fiendish puzzles 
to be solved. 

Snapper (price £9.95) is a colourful game 
where you guide vour 'snapper' through the 
maze, eating dots and fruit and avoiding the 
creatures that chase you. Complete with full 
sound effects, score and a ladder of high scores. 

Rocket Raid (price £9.95) sends you on a 
mission to raid a heavilv guarded Martian fuel 
depot. You must fly your rocket over mountains 
and through caverns, avoiding enemy missiles 
and dodging convoys of deadly fizzers. 

Increase your business acumen. 

^ 

Desk Diary (price £9.95) is an indispens- 
able program that can hold a file of several 
hundred names, addresses and telephone 
numbers. 

And View, a program that enables your 
machine, together with a printer, to operate as a 
fully operational word processor.(The program is 
in ROM, but can easily be htted to most BBC 
Micros by your local dealer.) You can find out 



more by sending for our 
free catalogue. 

How to get 
Acornsoft pro g rams. 

Ifyou're a credit 
card holder and would 
like to buy cassettes of 
the programs shown in 
this advertisement, or 
if you would like to 
know the address of 

your nearest stockist, just phone 01-200 0200. 
AlternativehvYou can buy the cassettes 

directiy by sending off 

the order form below to: 

Acornsoft, c/o Vector 

Marketing, Deninglon 

Estate,Welli ngborough, 

Northants NN8 2RL. 

Also use this form if you 

would like to receive 

the current free 

Acornsoft catalogue. 
Please allow 28 

days for delivery 

^Credit Card Holders. Ring 01-200 0200. 




R 




To: Acornsoft^ c/o Vector Marketing, Denington Estate, 
\^yiingborough, Northants NN8 2RL. 
Please send me the following:- 

proc;ra>i eiiM: QiJANxtD (XOBl. 

Creative Graphk-s £1745 



Word Sequencing £11^90 " 



OSF 



£24.H5 



FORTH £24.35 

l^hilosphers Quest £9.95 



snapper 



ppei 
ikct I 



-mrn- 



Rocket Raid 
Desk Uiarv 



£9.95 



(Code 
Acornsoft 
usic only) 

(SBXOl/SHDOl) 



(SBf:06) 



{SBL02/SBI)04) 



SBLOI/SBDOa) 



(SBGOl) 



{SBG04) 



(SBG()5) 



(SBBOI) 



TOXVL 



I enclose PO/cheque payable to Acornsoft Ltd. Or charge 
my credit card. 



Card Number, 



THlJ IS THi 116 







ZX Spectrum 

SOFTV\/ARE 



GORF IAN 

GORFIAN INVADERS, A Superb 4 screen 
machine code program with Invaders, 
Galaxfans, Firebird and Flagship. 
Multicoloured Hi-Resolution graphics and 
Sound Effects. 
For the 48K Spectrum, price £5.00 

KRAZY 
KONG 

KRAZY KONG. Another 100% machine 
code program, featuring 3 Screens of Hi- 
Res Gorilla, Barrels, Fireballs, Lifts and a 
Running and Jumping man who must 
rescue his girlfriend from the enraged 
KONG! For the Spectrum, price £5,00 

SPECMAN 






F ROGGER 






CENTIPEDE 

CENTtPEDE AND PAINTER 

By the time you read this our latest release for the 

Spectrum should be available 

Centipede is a full colour machine code arcade game 
where the object is to defend yourself with your Laser 
against a fast moving centipede which weeves in and 
out of the mushroom patch. There are other versions 
of this game but we think you'll prefer ours because 
we always strive for an extra dimension of realism, 
which makes all the difference! 
Painter, is another well loved Arcade game here you 
must paint in between the numbers on a 
multicoloured screen before you have to overlap. 
Price for SPECTRUM is £5.00. 



FROGGER AND SPECMAN, two excellent games for the price of one! 

SPECMAN is probably the best version of it's type with great machine 

code graphics and sound effects with 3 to 5 ghosts, power pills and a 

real munchie man who munches away in all directions unlike cheaper 

versions! 

Frogger, is a 2 screen superb representation of this arcade classic and 

has full colour Hi-Res Frogs, Cars, Roads, Logs, Turtles and Riverbank. 

Plus Super sound effects. 

Both on one cassette for the Spectrum, price £5.00. 

HOW AND WHERE TO GET €.- Tech Software PRODUCTS 

There are three ways to get the tape thai you require, firstly you can go to one of 

around fifty retailers in the UK and some more overseas, there is at least one in every 

town and several in major cities. 

Secondly you can ring our Telesales on 061-366 8223 and Alison or Shirley will take 

your order and tell you of any other games you might be interested in. 

Last the most popular way is to simply clip the coupon and send it to us at: 

CwTech, 184 Market St, HYDE, CHESHIRE, SK14 1EX. 



PIEASE SESO VI THE fO^lQSMNG 



I 



j MY NAMC AMO AOORCSS IS^ 
I 



I 



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C/D X "D O 

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Vow/^ Compiler l,vn> 



WIN A CAMPUtERS LYNX 

A Lyn* will b# «M»ictecf 10 (tw WinriOF of ihe I'owf Compntwr 
CwnpuliHX cqiripfllitifin To e-nm |hw compBtition, *ll fmi have ID < 
i* complinB thi cfDSfiword be4ciiA' 4nd Iin>i4l th< swilnnCi "A Lynx 
wouU bring Hjut llw annn»l in ma b^etuM. . " iri 13 WOfdt w taw* 

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SUBSCRIPTION ORDER 
FORM 

send me 12 issues of Your Computer 



Cheques should be made payable to IPC Business 
Press Ltd- Cash with otd&r please. 

Name , , , 

Addre^ - . . ..-..,,....-.., 

Signed 



D Subscript ion rate U.K. £8 

G Overseas f 14 

Amnall reies can be supplied on application to 
the SubacfiptJort Department 

YOUR COMPUTER MARCH 1983 



Your Computer Lynx 



RULES: 

^ The winner of the competition will be the person 
who enters a correct solution to the crossword and. 
in the view of the editor, completes the unfinished 
sentence in the most interesting way. 

% The rtame of the winner will be printed in the 
May issue of Your Computer. 

Alf entries must arrive at the Your Computer 
offices by the last working day in March 1983- 

% Each iperson mB^ entef the compfftition onty once< 

# Entries to the competition cannot be acknowledged - 

^ IMo employees of IPC Busings Press or their 
rajatrvas may enter the competition. 

9 The decision of the editor is final. 

# No correspondence on the resuH of the competition 
will be entered into. 

# IPC Business Press assumes no responsibility or 
liability for any complaints arising from this 
competition. 



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YOUR COMPUTER MARCH 1983 27 



yomuemRS. 



SCHIZOPHRENIA: DIVIDED VIEWS 

/was rather surprised ai the pompous and totally unhelpful 
reply lo Bradd France in Response Frame in January's issue of 
Your Computer, Coming from a magazine that publishes 
advertising for a computer known not to be available for months 
on end, that is> the Spectrum^ a high moral tone does not seem 
entirely appropriate. 

What right has Tim Hartnell to assume that someone wanting to 
stop an auto-run machine-code program must be also wanting to 
contravene copyright? There have been a couple of occasions 
when I have unthinkingly made a machine-code program with a 
bug in it an auio-run version, and then Saved it to be safe. A lot of 
typing would have been avoided by having an ability to stop 
execution and rescue the item. Secondly I have found it a very 
valuable way of learning programming techniques in machine 
code. I do hope that Tim Ilartneil is not proposing to have the 
copyright law^s changed to make even study illegal 

If the user of a stopper program docs in fact intend to infringe 
copyright, then what business is it of yours anyway? However, if 
you do feel that '*it would be highly irresponsible to publish*' a 
program intended to break into machine code then perhaps you 
would care to explain why you did publish one in the December 
Software File? Gino Gracin's very useful "list self starter" was just 
w^hat Mr France needs, but as I imagine that your curiously-mixed 
morals will prevent you publishing this to let him know then I can 
only hope that he found it for himself 

While I am at it can I suggest that your contributor to Response 
Frame sticks to answering questions about computing — which he 
is evidently competent to deal with. I have in past issues seen some 
entertaining replies to TV and tape recorder queries. 

A Jaques^ Urmston, Manchester, 



BUG SPOTTER 

|A)u only do it to annoy, because 
^ you know it teases! All those 
errors in published machine-code 
programs. Three recent corrections, 
which may be helpful to your other 
readers, are as follows: first, Hopper, 
January 1983, addresses 16854 to 7 
were left out and should be 
22 D3 40. 16974 should contain B3, 
and 16975,6 should read 20 FB. 

Second, Snake, February 1983 
Software File, addresses 16574 to 
16581 omitted, putting all sub* 
sequent addresses out by eight bytes. 
These addresses should contain 01 
12 13 11 01 00 18 16. 

Third Maze Chase as listed, also 
Februarj^ Software File, gives a set of 
bars but no maze. Address 16564 
should contain 00. All the above 
codes are hexadecimal numbers. I 
know it is good for us to debug 
machine-code programs, but this can 
take longer than entering them, 

yRG Nash, 

Botley, 

Oxfordshire. 

RAM WRINKLE 

fj#hen the BBC Basic conversion 
|r|f board is fitted to an Acorn 
Atom, it disables the Atom*s bus 
buffers for addresses in the range 
4000-7FFF. This is sensible when in 
BBC mode, as this area of memory is 
then used for I/O, the utility ROM, 
and the graphics RAM. But when in 
Atom Basic mode, this area could 
otherwise be used by external RAM 
to extend the text space. 

Luckily, a simple modification lo 
the BBC Basic conversion board will 
enable the bus buffers for this 



address range when in Atom mode. 
It involves bending pin 11 of IC14 
up so that it no longer makes contact 
with the socket, then connecting this 
pin to pin 12 of IC 12, 

Readers may also be interested to 
note that with the extra 2K bytes of 
RAM provided on the BBC Basic 
conversion board, the total RAM in 
the system becomes in the BBC 
nKxic: 

8K from 0000 to IFFF 
6K (graphics) 4000 to 57FF 
and in the Atom mode 
IK from 0000 to 03FF 
7K from 2000 to 3BFF 
6K (graphics) 8000 to 97FF 

Mike Lord, 

Basildon^ 

Essex, 



FAST SLIDE 

/trewart Stalhvorthy obviously 
^ went 10 a great deal of trouble to 
prepare the Z-80 Slide Show code — 
Software File, January 1983. The 
essence of the job can be done with 
the single instruction LDir, and 
roughly three times faster, as 
follows: 



Code 

21 A4 9C 



1100 40 



01 00 IB 
ED BO 



C9 



Assembly Comment 

LD HL,40100 first byte of 
saved 

display, the 
same as the 
published 
example. 

LO OE, 16384 first byte of 
display fite 
proper 
byte coum 

LD1R block 

transfer until 

BC^O 

RET 



LD BC,e912 



12 bytes of code* versus Stewart's 
48> and relocatable! The whole thing 
really docs operate with astonishing 
speed; it takes about six milliseconds 
to execute the whole routine once on 
my Spectrum. Try alternating 
between two Saved displays — it is 
enough to make your eyes water! 

Incidentally, I detected a bug in 
Stevvan^s listing; address 40029 
should contain 239, not 238 as 
shown. Fortunately it does not 
matter; the JR points to the last byte 
of LD HL,nn at 40010 which 
decodes as LD B^B. 

D WAIbery 

Fleet, 

Hampshire. 

BUZZING 

ZX-81 users may be interested to 
know that one reason for 
loading problems may be the close 
proximity of TV set and tape 
recorder. Check by running the 
recorder on play without a cassette 
or with a blank tape and with the 
volume turned up high. When 
placed near a working T\^ sety 
particularly at either side, a harsh 
buzz Will be heard. If a ZX-Sl set to 
Load is then connected, a pattern of 
bright bands reminiscent of correct 
loading but closer and narrower will 
be seen even though no program is 
being played. Previous to this 
discovery I had to strike a balance 
between too little volume and too 
much. Too much volume %^s really 
interference from the scan coil in the 
TV. Now with a cassette player two 
to three feet distant, I can use full 
volume and get perfect loading. 

A second discover)' is that an edge 
connector with the trade mark 
UECL has a contact design which I 
consider gives much more positive 
contaa with the ZX-Sl circuit 



board. I have also carefully removed 
the thick layer of solder from the 
ZX-81 contacts. I can now deliber- 
ately rock my home-made memory 
board back and forth without losing 
memory; previously even a slight 
vibration could cause a maddening 
crash. 

Could I suggest that computer 
reviews be aimed rather more 
towards the user like myself who has 
little interest in games. For example, 
a computer without Arc Sine and 
Arc Cos is an anachronism to me. 
Accuracy of working can be of 
interest since 8 figures is sometimes 
insufficient for one of my interests, 
astronomical calculations. A point 
which i have never seen mentioned 
is the resetting of variables — that is, 
data to zero — if a program line is 
altered. This is most frustrating 
when debugging a program, but 
with my ZX-81 I can go along 
happily editing and restarting at the 
corrected line. 

B Manning, 

Stakenbridge, 

Worasiershire 

1K CHESS 

rhc code presented for the three 
articles on chess is correct. If 
you are having problems then Vm 
afraid an incorrect number has been 
typed in and you arc finding out 
first-hand the pleasures of machine- 
code programming, 

I did omit to lell you of two Pokes 
prior to saving the IK working game 
which provide the moved King or 
Queen's pawn. Prior to tvping 
RAND USR 18542 type 
POKE 17241,0 
POKE 17252,53 
These move the King*s pawn 
forward then 

RAND USB 18542 



STRANGE DISSERTATION 

rime is envisaged by some thinkers as particulate. That is to 
say, time is composed of discrete particles. These particles are 
known as chronons> and being particles they must have mass. 
Since they have mass it follows that they must occupy space. 

The rate of flow of time is demonstrably the same in all parts of 
the universe — except when very high speeds are considered — so 
much is common knowledge. 

I am convinced that this state of affairs does not apply to the 
space in the vicinity of microcomputers and their associated 
paraphernalia. My theory is that microcomputers interfere with 
the space-time continuum in such a way that the density per unit 
area of chronons in the vicinity of these objects is very much 
reduced: it can be seen that in a volume of space where there are 
few chronons, the amount or quantity of time will be less than in a 
normal volume of space. 

A few minutes near a microcomputer may be equivalent to an 
hour or more in a normal atmosphere, so that when your 
wife/husband/girlfriend/boyfriend calls you away from your 
computer, and you reply, "five more minutes'', is it surprising that 
an hour or more of norma! time passes? 

This theory also explains the 28 days phenomenon. For 
example, it is not widely known that Clive Sinclair is convinced 
that the whole world is playing an immense practical joke on him 
— he believes that all his computers were delivered within 28 days. 
What he is unaw^are of is that the 28 days were measured in the 
rarified chronon atmosphere surrounding his computer factory. 
Dominic Purdue^ North Jesmond, Newcastle-upon-Tyne. 



28 YOUR COMPUTER. MARCH 1983 



and Save Uiis on lo tape or type: 
POKE 17242 J 28 
POKE 17253,53 
moves Queen's pawn forward. 

These Pokes move Queen's pawn 
forward then: 

HAND USR 18542 
and Save on to tape. 

If you give up, but stiU would like 
the game, you can probably obtain a 
IK chess by either Artie or Sinclair 
from your local supplier. If in 
difllculties write to me enclosing £3 
and I will return a tape of the 
playing program. 

David Harm, 

Crou'boraugh, 

Sussex. 



CREEPY LIFE 

^ome errors crept into my ZX-81 
^ life program in the Januar>' 1983 
issue of Your Computer, In the 
machine-code list, figure 1, the code 
at location 16603 should read 6,32. 
Also in the Basic listing, line 135 
should read Goto 40. 

PJ Whittle, 

Chobham, 

Surrey. 



ZX RAND 

^hc Rand statement on the ZX-81 

f and the ZX Spectrum is very 

usclliL It is used to call a lot of 

machine-code routines in the form: 

20 RAND USR 16514 

However, the Rand statement can 
be used for a lot more. When Rand is 
usedi the number following the 
Rand statement is placed in locations 
16434 and 16435 — see page 178 in 
the ZX-81 manual. On the XZ-81 
these locations can be used to pass, 
numbers to machine-code routines 
or for a quick conversion routine. 

Suppose you wanted to Poke N 
into locations 16514 and 16515, 
normally the program 
10 REM XX 
20 INPUT N 

30 POKE 16614,N-tNT(N/2S6)'256 
40 POKE 1$515JNT(N/256) 
would be used, using Rand the 
following could be: 
10 REM XX 
20 INPUT N 
30 RAND N 

C POKE t6514,PEEK 16434 
50 POKE 1 651 &, PEEK 16435 
This saves 13 b>tes on the original 
and takes about half the time to 
execute. One word of warning. 
Having N=0 will not work as 
unpredictable results will be put into 
locations 16434 and 16435. The 
same technique can be used on the 
Spectrum but the locations that 
Randomise sets will need to be 
looked up. 

Finally a four-line program to set 
RAiMtop. The RAM size is held in 
Nthat isN-1 for IK 
10 RAND 1024*(16+N} 
20 POKE 16388.PEEK 16434 
30 POKE 16389, PEEK 16435 
40 NEW 

Each line can be entered as a direct 
command. 

Tim Griffith, 

Ccfvemry, 

Warwickshire H 




EVrrORIAL 



When the finely-worded comparison tables of the 
micro-makers traw! for new^ buyers, only the 
computing-wise slip through the net. They make 
sure, that when they are eventually caught it is 
because they wanted to be: ihcy know how to read 
between the lines. The rest of us swim blindly into 
those grids which compare the features offered by 
the new wonder micro with its competition. 
Naturally^ only the advertised machine has a tick in 
every box, 

OccasionalJy we may wonder about the 
importance of the green plastic securing screws 
which the table tells us only the touted micro can 
boast. But usually we swallow claims for speed, 
memory and resolution hook> line and sinker. 

Of coursCj these claims are rarely imtrue, but 
they are often only relative facts and depend largely 
on the knowledge of the would-be buyer for correct 
imerpretaiion. You might not be hugely impressed 
by a car whose adverts major on the fact that it 
features a complete interna! combustion engine » On 
the other hand, a total newcomer to computing 
might be awed by the promise of a silicon-wafer 
central processor. 

Sometimes the glossy brochures can be unhelp- 
fully obscure, Jusi how many beginners really 
needed to know that the ZX-81 offered a full 26 
For-Ncxt loops? 

Against that, facts which arc genuinely useful are 
frequently omitted. The amount of RAM remain- 
ing after the operating system and high-resolution 
graphics have helped themselves is the kind of 
information that can sway a buying decision. 

This is because it is the type of fact that can 
reduce the 48K Lvnx to an 11 K machine, and the 
32K BBC Micro to an 8K one. The £50 Microdrive 



promised in the Spectrum adverts seems to offer 
mass storage at a micro price, but for the last six 
months there has been no reference to the £30 
interface you will need to drive it. 

The modern buyer must also be a student of 
relativity to be able to understand the "high** in 
high resolutionj the "low" in low cost, or the 
"fast** without which Basic would no longer seem 
complete. 

Although "advanced** in the context of graphics 
presumably means user-defmed> a smattering of 
semantics comes in handy when trying to decide 
what "professional** means when applied to a 
piastic-capped rubber keyboard. Descriptions of 
sound and colour facilities contain the same sort of 
ambiguities — ambiguous, at least, for the beginner. 
One of the solutions to these problems is increased 
computer literacy. With a buying public as well 
informed as in the car market, the home-computer 
manufacturers will be obliged to be even more 
precise in iheir publicity machinery. It will also 
mean that the buyer will recognise which features 
are common to alt micros and which are specific to 
the one advertised. Being told that Basic is resident 
in ROM does not have quite the same glamour if 
you know that this is the rule rather than the 
exception. 

After years of complaints about the misleading 
claims of motor companies for their cars' petrol 
consumption, legislation was needed before 
independently-assessed mileage figures were intro- 
duced. 

Unless the industry can come up with a set of 
mutually acceptable standards by which micros can 
be judged, it may find similar measures forced 
upon it. H 



How to write for Your Computer 

We called this magazine Your Computer precisely because we welcome your 
views, tips and hints and even your criticism of machines and software in general. 
If you would like to see your name in print, whether on a Software File program or 
a full-blooded article, here is how to go about it. Ideally, all articles should be 
typed double-spaced on one side only of uniform sheets of paper. If listings can 
be dumped directly from a printer — you can always use a friend's or user group's 
— this minimises the risk of error. In a perfect world a cassette would 
accompany the article. That considerably speeds up the checking process. Not 
only do you get to air your own discoveries and opinions, but we will even pay 
you for the privilege. We pay £35 per published page — that's as it appears in the 

magazine and includes illustrations. 
Why not give it a try? You have nothing to lose but your postage. 



ABC 






Editor 

TOBY WOLPE 

Assistant Editor 

MEIRION JONES 

Staff Writer 

SIMON BEESLEY 
Sub-editor 
PAUL BOND 
Editorial Secretary 

LYNN COWLING 
Editorial: 01-661 3144 

Your Compute^ Quadrant House, The 
Quadrant, Sutton, Surrey SM2 5AS. 

Subscriptions: U.K. £8 for 12 issues. 

Typcseiting by In Step Ltd, Londoo ECK 
Printed by Rivefside Pre» Lid, Whitstab»e, Kent, 
Published by IPC Efcciricat-Ei^clfQr^c Pfess Lid, Quadrant 
House. The Quadrant, Sutton, Surrey SM2 5AS. Tol: 01 661 
3500 Tetex/9!dms 8920S4 BiPRESG. ISSN 0263068S 



Advertisement Manager 
PHILIP KIRBY 01-661 3127 
Assistant Advertisement Manager 
PETER RICE 01 661 8441 
Advertisement Executives 
BILL ARDLEY 01-661 8484 
NIGEL BORRELL 01-661 3127 
Midlands Office 
KEITH SALT 021-356 4838 

Northern Office 

RON SOUTHALL 061 -872 8861 

Advertisement Secretary 

JEANETTE MACKRELL 

Olassif i^d 

GILLIAN JOHNSON 01 661 3036 

Publishing Director 

CHRIS HIPWELL 

© IPC Business Press Ltd 1983 



YOUR COMPUTER, MARCH 1983 29 




H€WS. 



£99 Creativision is one 
up on rival computers 



CoLOCR, SOUND, and 16K for £99 is 
rapidly becoming an industry 
standard, but the Creativision goes 
one better — literally — it has 1 7K of 
RAM, 

Although the standard Personal 
Computer unit looks more like a 
video game than a home micro, the 
unit contains a 6502 processor as 
found in the BBC Micro, the Vic 
and the Oric and is capable of being 
expanded to 64K RAM. Resolution 
is 256 by 192 with 16 colours three 
sound channels and a noise channel. 
The 12K ROM includes a Microsoft 
Basic. 

The standard keyboard combines 
ihe idiosyncratic layout of the M2- 
80K with the feel of a ZX-81 with 
the cunning innovation of a half- 
inch gap splitting the board in half 
so that the two joysticks can be lifted 
ofTthe front panel. 

The optional keyboard — illus- 
trated — is at normal typewriter 
pitch but it still lacks a full-size 
spacebar. The screen display is 28 
columns of 24 characters each com- 
posed from a five*by-seven fount. 

A purpose-built cassette recorder, 



1 


7sm 




1 L 

Game 


9r 

Company 


Machine 


■Hobbit 


Melbourne 






House 


Spectrum 


■Black 


Carnell 




Crystal 


Software 


ZX-81 


■Spectral 






Invaders 


Bug Byte 


Spectrum 


■ Krazy 


Software 




Kong 


Cfty 


ViC'20 


■ Frogger 


JL 






Software 


2X81 


■ Moons of 






Jupiter 


Romit 


Vic-20 


■Or biter 


Silversoft 


Spectrum 


■Martian 






Raiders 


Audiogenic 


Vic-20 


■ Defender 


Atari 


Atari 


■Jetty 






Monsters 


Comnw- 






dore 


Vic-20 


■Timegat© 


Quicksilva 


Spectrum 


■ Right 






Simulation Psion 


ZX-81 


■Star 






Raiders 


Atari 


Atari 


■Ground 






Attack 


Silversoft 


Spectrum 


■ Penetrator Mel bourne 






House 


Spectrum 


■Gauntlet 


Cotour- 






matic 


ZX-81 


■3D 






Defender 


J K Grey© 


ZX-Sl 


■Space 






Pirates 


Bug Byte 


BBC 


■ Planetoids Acornsoft 


BBC 


■ Hoppit 


Commo- 






dore 


Vic*20 




memory' expansion units and Cen- 
tronics and RS-232 interfaces can be 
plugged into the side of the standard 
unit. Every 16K of additional 
memory costs £39 as does each 
interface, 

A Modem and a disc drive will also 
be available when the machine goes 



on sale in June, along with printers 
and acoustic couplers. 

ROM cartridges will offer 
Extended Microsoft Basic and games 
ranging from old arcade standards 
such as Sonic Invader and Crazy 
Chicken to the intriguingly named 
Police Jump. 



Forth of Firth 
first for BBC 

R Q Forth, written by Roger Q 
Firth for Level 9 Computing, is a 
Forth compiler for the BBC Micro. 
It fits into the model A's 16K, 
leaving space for about 200 lines of 
user program. Major features 
include a full screen editor, 260 
predefined Forth words, and an 
unusual provision for using 
recursion. 

Firth Forth programs run up to 10 
times faster than BBC Basic — itself 
probably the fastest version of Basic 
on any home micro. 

The compiler comes on cassette 
together with a 70*page manual and 
costs £15 inclusive. To go with it, 
Level 9 Computing supplies a Forth 
toolkit which adds a further 200 new 
functions and includes such utilities 
as a 6502 assembler, turtle graphics 
and fwx decompiler routined. This 
too is accompanied by a full manual 
and costs £10. 



Light at the end of the Tunnel for 
Evans the Top 20 games writer 



With more and more of the sales of 
home computer games concentrated 
in the hands of a few large software 
companies it is unusual to find a 
highly successful company run by a 
staff of two. Malcolm Evans writes 
the programs for New Generation 
Software and, assisted by his wife> 
also handles production and 
marketing. 

All his games have sold in large 
numbers and he has even had the 
distinction of having two hit 
programs in Your Compuur*$ Top 
Twenty at the same time. 14,000 
people have bought his Spectrum 
program* Escape, and his latest 
release, 3D Tunnel, looks set to have 
the same success; already WH Smith 
has ordered 10,000 copies of the 
game. 

He wrote his programs for the 
ZX-81 - 3D Defender, 3D Monster 
Maze and Full Screen Breakout — 
for J K Grcye Software. At the time 
he was employed by Sperry in 
Bristol as head of the Aiicro- 
proccssor Applications Group. 
When Sperry offered him the choice 
of moving elsewhere or redundancy 
he decided to strike out on his own 




with New Generation Software. 

3D Tunnel took Malcolm Evans 
three months to complete. He 
developed the program on a Sharp 
MZ-80B before downloading the 
machine code into the Spectrum. 

Like Escape, 3D Tunnel follows 
an original idea and is not }ust 



another version of an arcade 
favourite. The player has to pass 
through five stages, destroying bats, 
rats, toads and spiders before 
meeting the final obstacle, a London 
underground train. The game costs 
£5.9S and will run on both the 16K 
and 48K Spectrums. 



30 YOUR COMPUTER. MARCH 1 983 



News. 








Texas TI-99/2: 
a new frontier 

Texas instruments has now 
released derails of the TI-99/2 
described in last month*s news item. 
It will be launched in September for 
around £75. The screen display is 
monochrome but with the same text 
format and pixel resolution as the 
TI-99/4A - that is, 24 by 32 and 192 
by 256. 

In addition Texas is introducing 
new low<ost peripherals and soft- 
ware for the TI-99/2 that will also 
work with ihc TI-99/4A. These will 
be on the market in May this year 
and include a four-colour 
primer/plotter for £150 and a £120 
digital tape drive with a data transfer 
rate of 8,000 baud. 

Most peripherals for the new 
system will plug into a Hex-bus, a 
peripheral interface connector* at 
the back of the machine. At the 
initial launch 20 programs will be 
available. 

This €700 silver ring - the first 
prize along with £1500 worth of 
Acorn hardware and software in 
the Your Computer />4corn5o/r 
Castle of Riddles competition — is 
still looking for an owner. Early- 
birds received their cassettes in the 
post on the morning of February 
1 6, Acornsoft's managing director 
claims that the Castle of Riddles 
adventure game is extremely 
difficult and that people entering 
the competition a few weeks after 
the opening date would probably 
still be in the running. A winner 
must be found by March 31. 




Tomy the toy-maker's 16-bit micro 
is not just a Japanese plaything 




Quiclcsilva fast to spot 
new software talent 



QUICKSILVA IS AMAZED at the 

number of new programmers out 
there just w*aiting to be discovered. 
A series of advertisements for new* 
talent drew such a good response 
that it was able to commission new 
programs for the whole range of 
home computers. 

As a result new Vic and Atari 
games have now been released along 
with new titles for the Spectrum and 
ZX-81. Coming shortly are games 
for the Dragon, BBC Micro and 
Lynx. 

Quicksilva has also taken on the 
marketing of the Pixel range of 
games for the Vic-20 and ZX-81. 
Production director, Mark Eyles> 
says that the company seems to be 
turning into more of a publishing 
house than a software company. 

He added that Quicksilva felt thai 
programmers were very important 
and should be given the same credit 
for their programs, in advertise- 
ments and on the packaging, as 
authors receive for their books- 
Enthusiasts who enjoy a particular 
program could then look out for the 



author's next release. 

Quicksilva now has distributors all 
round the world. Mark Eylcs jokes 
that if the company continues to 
expand at its present rate it w^ould 
achieve multinational status znd **we 
will all be tax exiles before long." 



Tov TOVt'N has already moved into 
games machines and is now heading 
in to home computer land. Tomy, 
the Japanese toy manufacturer, is 
launching the 16-bit Grandstand 
Computer with 16K ROM and 16K 
RAM for around £170. 

The standard machine offers only 
19 Basic commands and its main 
strength lies in its graphics facilities* 
A built-in character generator allows 
the user to define a character on an 
eighi-by-cight grid in the lower part 
of the screen and then position the 
character with the cursor in the main 
display. 

16 colours are available in a 
resolution of 256 by 192. Up to four 
sprites can also be designed and 
moved by program commands or 
under joystick control. 

Games cartridges can be plugged 
in and there is provision for further 
ROiM cartridges to extend the Basic 
and to handle a printer and a floppy 
disc. The Grandstand Computer has 
a full 56-kcy keyboard and will be 
supplied with two games paddles. 

£49 Modem 
widens net 

MiCRONET sao, the Prcstel database 
for personal computers, was tech- 
nically opened on February 21. 
Networking interfaces are being 
oftered to the first 10,000 sub- 
scribers for £49. These include all 
the hardware and software needed to 
link the computer up to Prestel via 
the public telephone system — an 
acoustic Modem, power pack, cables 
and the necessary software. 

Adaptors are now ready for the 
BBC, and Tandy Colour Computer 
with the necessary software supplied 
on tape or disc. The Spectrum and 
Dragon adaptors which should be 
released in March will be in the form 
of plug-in cartridges and contain the 
software in ROxM. 



The Spectrum Desk Console is designed to house a Spectrum and all its 
peripherals. There is room for a printer, a cassette recorder and the power 
unit as well as an RS-232 interface and up to two Microdrives, Made from 
heavy-gauge ABS plastic, it is available from Traffic Technology, PO Box 
Z Warminster, Wiltshire, BA 12 7QX, for €42. 18 inclusive. 





1^ ^ 


1 




■ i 


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YOUR COMPUTER, MARCH 1983 31 




tQi]© 



FOR OWNERS OF 

IfD 




fpT?mnnm 
lb y uuiiJilU D 

fiD 



D 



uu 



. large savings 

on top software 

All programs are, at least, 10% cheaper than normal and, 
each month, the best of the most recent software is made 
available to members at 20% less than normal. Postage and 
packing is free on orders of two or more programs for 
delivery within the UK; ordering and payment are simple, 
and quality is guaranteed. 

no obligation 




MICROCOMPUTERS 



Buying software for your computer is a gamble. Apart from 
the occasional review and, perhaps, a recommendation from 
a friend, you have precious little information upon which to 
base your purchasing decision. 

Advertisements and clever packaging can make the the 
worst programs appear tremendous. It is not until you have 
^gambled' your money that you discover how good they 
really are. Some are only slightly different to others you 
may already own; many are not as good as you would be 
entitled to expect; and others are just a complete waste of 
money. Of course, there are some excellent programs 
around, and many more appear monta. Now there is a safe 
way of finding out about them. 



- free membership - 

THE MICROCOMPUTER SOFTWARE CLUB was started 
to make software purchasing easier, cheaper^ and less risky. 
Membership is completely free of charge, as is the monthly 
Newsletter, Every month members receive full details on 
the best and latest programs available for their computer 
and, simply and confidently, are able to order any of the 
programs they choose at substantially less than normal 
prices. 



Members are not obliged to buy a fixed number of programs 
from The Club, They buy what they want when they want. 
Whether it is one program in a year or one a month, they 
know that when they buy from THE MICROCOMPUTER 
SOFTWARE CLUB they are buying the best programs at 
the best prices. 



— free Newsletter - 

Our latest Newsletter offers progra/ns from most leading 
suppliers - and from a few that, perhaps, you do not yet 
know. A program has to be good, very good, before it is 
recommended to members. It also has to be reliable and, 
even before the members' discount, it has to be good value 
for money. Subject coverage includes adventure, arcade, 
education, strategy games, household applications, family 
games, business, utilities and programming aids. 

Remember, membership is completely free of charge and 
you are under no obligation to buy anything from The Club 
unless you really want to. If you own or use a ZX8 1 ( 1 6K)» 
Spectrum(16K or 48K), BBC (A or B), Dragon 32, or VIC 
(expanded or unexpanded), you should join THE CLUB. 

JIODK] W°)[DZiSf 

v->' THE MICROCOMPUTER SOFTWARE CLUB 
i^-^^^^ P.O.Box 166, Oxford, 0X2 9BJ,.EngIand. 



Free membership application 



Please accept my application and enrol me as a 
member of The Slicrocomputcr Software Club. I 
understand that membership is free of charge. 

As a member I will receive the Club Newsletter 
free of charge and will be entitled to benefit 
from any savmgs offered to members on selected 
programs for microcomputers. 1 may cancel my 
membership at any time. 



NAME I I M I M M 



ADDRESS M I I I 1 I I I 



i I M M 1 I I 



When completed, return form to:- 

THE MICROCOMPUTER SOFTWARE CLUB 
P.O.Box 166, Oxford, 0X2 9BJ, Kngland. 



CITY M [ I I 1 I I I 
POSTCODE 1 I I I I I I I I 



COMPUTER MODEL 

SIGNATIJRI- 



I I I 1 1 I t I I 1 I M I M 



I I I i i I I I M I I I I M 



I M I I I I i 1 I I I I M I 



I M I I I I I I M I I I 1 I 



I I 1 I I I 



I I 1 I M 



AGE (If under 18) 
COMPUTER RAM 



32 YOUR COMPUTER. MARCH 1983 



jam SXTRA USA 



Mattel's new age dawns with 
Aquarius — the 16-colour micro 



Texas boldly 
goes to school 



At last the big American games- 
machine makers have realised thai 
people prefer lo play games on 
proper computers that they can use 
for other purposes. Matiel — which 
makes the Intellivision — is no 
exception. Not only has the com- 
pany now launched the Aquarius 
computer in the States — Britain 
will have to wait until September — 
but it has also launched an upgrade 
kit for the Intellivision. 

At less than £100 the 4K, 
1 decolour Aquarius will be a strong 
rival to the Timex 2000 in America 
but the planned £120 British price 
tag will not frighten Sinclair or Oric. 
The rubber keyboard does not have a 
full-size spacebar but a keyboard 
overlay allows you to make use of a 
single-key entry option. 

The British version will probably 
have three sound channels and the 
screen w»ill have 320 by 192 resolu- 
tion. The Z-80A based machine will 
run Microsoft Basic. 

In America an extra £150 will buy 
you a tape recorder, thermal printer, 
joysticks and an expander. A similar 
package will be available here 
though the price will be higher. 

A buili-in RS-232 should en- 
courage Aquarius buyers to consider 
the Modems and floppy disc drives 
which Mattel will also be supplying. 
Mattel claims that the Aquarius will 
be able to run CP/M. 

Meanwhile, anyone who thinks 




their Intellivision is not too bright 
will welcome the Intellivision 
Computer Adaptor. This plug-in 
keyboard also boosts the machine's 
memory by 2K and makes Microsoft 
Extended Basic available along with 
a six-channcl sound generator. The 
price will be around £80. An £80 



piano-style 49-kcy keyboard in* 
corpora ting a synthesiser also plugs 
into the adaptor. 

Both the Aquarius and the 
brighter Intcllivisions will be able to 
run a Logo cartridge, a Basic teach- 
ing package, and games based on 
Scooby-Doo and the Flint stones. 



Computer literacy is big business in 
the United States and the new Texas 
TI-99/2 is aimed squarely at this 
market. No colour, no sound, but a 
16-bit computer whose programs 
and peripherals are compatible with 
the established Tr-99/4A. 

It comes with 4.2K of RAM and 
24K ROM and is available in the 
Slates for around £60 — for U.K. 
details see page 51. Expandable to 
32K RAM with a rubber keyboard 
and full-sized spacebar, this is a very 
real competitor to the American ZX- 
81, the Timex 1000. 



Japan's JR steps in for Panasonic 
and NEC iaunclies PC-6001 



The |AP.\nese have entered the U.S. 
micro arena. Panasonic's £150 
machine boasts 32K of RAM and 



16K of ROM, with 2K separate 
video RAM and 2K character RAM. 
It has a full-size spacebar and 




Low U.S. price 
for Spectrum 

The timex Sinclair 2000 — alias the 
American Spectrum — sells over 
there at around £95 for the 16K 
version and £125 for 48K. Air vents 
on the back, a different ROM, a 
ihree-voice sound chip and provision 
for two joysticks are new features, 
plus a more rugged printer. Do the 
U.S. prices hint at future U.K. 
prices? 



separate cursor control keys. The 
CPU is a Panasonic chip — the MN- 
I800A — which is equivalent to the 
6802, not a chip that many will be 
familiar with. 

The JR-2000U, which employs its 
own brand of Microsoft- type Basic, 
has a choice of eight colours, RGB 
and TV outputs. Where Panasonic's 
new baby may be at a dis2dvantage is 
in its relatively low resolution of 64 
by 48 in the graphics mode. 

NEC has also launched its 
PC*6001 which sells for around 
£200. Ii has a rubber keyboard, 16K 
RAM, 16K ROM, and can be ex- 
panded up to 48K. Nine colours are 
usable and text and graphics can be 
freely mixed. 

Spectra Video's new micro — 
below — costs around £250 and 
claims to be CF/M compatible. It 
has 32K HAM and 32K ROM, 
offers 16 colours, sprite graphics 
and pixel addressable colour. 
RAM can be expanded to f44K 
ROM to 96K. It has rubber keys, 
full spacebar and a joystick on the 
console. 




YOUR COMPUTER, MARCH 1983 33 



Tonight On Your Micro 





CAN YOU SURVIVE PENETRATOR? 

PENETRATOR IS the most amazing and 

sophisticated arcade game yet devised for 

the aSK Spectrum. Features include training 

mode, unique customizing, superior 

graphics, excellent sound and more! 

xassette £6.95. 




RESCUE A VIC PRINCESS 

A multi-part adventure for the standard VIC 201 

Ail you have to do is find the castle, defeat 

the dragon, find your way through the 

labyrinth, kill the wizard and rescue the 

Princess. And that's not half of it! THE WIZARD 

& THE PRINCESS cassette only £5.95. 



CONVERT YOUR VIC INTO AN ARCADE 

MACHINE 

Amazing arcade action for the standard VIC 20 

with 5 new exciting games from Clifford 

Ramshaw: ALIEN BLITZr INVADERS? GROUND 

ATTACK, STORM and SPACE ROCKS* (games 

marked * contain machine code). You must 

have the VIC GAMES PACK cassette -only $5.95. 




THEHOBBITISHERE! 

Experience the fantasy of J. R. Tolkien's 

"HOBBIT" on your 48K Spectrum. Danger, 

adventure and excitement are all part of it in 

words and graphics, but it is you who must 

solve the problems. Special features never 

seen before, THE hobbit is the program 

everyone is talking about £14.95. 



MELBOURNE HOUSE PUBLISHERS 



: Please send me your free catalogue. 
Pteasesendme: 
Books 

SPECTRUM 

Z Understanding Your Spectrum 
Z Spectrum Machine language 

For The At>so^ute Beginner 
C Over The Spectrum 

VIC 20 

D VIC innovative computing 

DRAGON 

z: Enter The Dragon 



Orders to: 131 Trafalgar Road, 
Greenwich. London SEIO 



Correspondence to: Glebe cottage, 
station Road. Cheddlngton, 
Leighton Burzard. beds lu7 7KA 



Trade enquiries 
wftcome. 



ZX81 



£7,95 

£6.95 
£6.95 



£6.9$ 



£5.95 



Machine Language Made Simple 

fortheZX80SzX81 £8.95 

:. Not Only 30 programs £4.95 

"J Understanding Your 

ZX8t ROM £8.95 

C complete Sinclair Basic 

course £17.50 

" Baste course cassettes £2.50 

:j Completestnclair ZX81 Rom 

Disassembly Part A & B £9.95 



cassettes 

16K SPECTRUM 

:: overTheSpectrumP»*o.i 
^: OverlheSpectrumNo. 2 
3 Over The Spectrum No. 3 
a Programs from Spectrum 
Machine language Book 



£5.95 

£5.95 
£5.95 

£5,95 



48K SPECTRUM 

Penetrator £6.95 

^ The Hobbit £14.95 
STANDARD VIC 20 

" VIC innovative cassette 1 £5.95 

:; vicinnovative cassette 2 £5.95 

_ VIC innovative Cassette 5 £5:95 

D VIC Games Pack £5.95 

C The wizard & The Princess £5.9S 



All prices Include VAT where applicable 



All Melbourne House cassette software is unconditionally guaranteed against malfunction. 
Access orders can be telephoned through on our 24hour ansafone (01 J 858 7S97. 



I enclose my cheque/money order for £ 

Please debit my Access card uo, 

signature 

Address , _-=._ 



Please add 80p for post and pack £. 
TOTAL f- 



.80 



_£xp)rydate. 



Name. 



. Postcode 



YC2 



MELBOURNE HOUSE PUBLISHERS 




NOW . . . KUK ZX SPECTHuwi U£>tHS tvtrtYwHEht 

ULLERBOX... 



A NEW DIMENSION IN 
SPECTRUM CAPABILITY 

If s easy to see why the ZX Spectrum is outselling all the other small 
colour computers, it really is a marvel of new technology. 
Equally marvellous is the new Tuller Box* for your Spectrum. 
Sound Quality is improved enormously with the built in Audio 
Amplifier w\n\oh works with all Spectrum programs. The Sound 
Synthesiser will make any sound you want to design: explosions^ 

laser blasts, trains, birds eta It's based on the popular 
G1 -AY-S-SSI 2 chip, and is supplied with a demo program. 
Finally, the Joystick Port enables you to use any low-priced 
TMari/Commodore joysticks with your programs. 
The Fuller Box fits neatly on to the back of your ZX Spectrum^and does not 
Interfere with any peripherals, PRICE (INC VAT) 

including the new Spectrum microdrives O O Q Q C^ J^ Qn r\ r\SL r% 

But the story doesn't end there! The Fuller Box has been designed to perform many other functions, 
and extra expanded versions are already available. 



m.'^ 






.-^^^.• 
m^'^ 



The Fuller Orator turns the 

Spectrum sound effects into speech! 
It plugs easily into the Fuller Box, and can say 
anything typed on the keyboard or from your 
programs, via the ALLOPHONE synthesiser. 
Complete v;ith Demo cassette: 

£39.95 +80PP&P 



Fuller FD42 System 
NOW FOR ZX81 or ZX 
^^ . SPECTRUM 



This famous, best selling 
product immediately 
converts your ZX 
Computer into a sturdy, 
"attractive and professional unit, 
full size typewriter keyboard. A 
tough plastic case encloses the 
keyboard, P CB. and power supply. It has 
42 keys including all the ZX81 /Spectrum graphic 
characters printed on them. The full travel key switches 
have gold plated contacts and guaranteed life of 10^ 
operations. ITS SO EASY TO INSTALL! You simply 
unscrew the ZX PCB from its case, screw it to the FD 
case, and plug in the keyboard. No soldering or technical 
knowledge required. 

NOW ALL ONE PRICE! £29.95 (inc. VAT) + £2,50 p&p 

1 6K Expansion, Fits onto back of case or inside using 
a RAM Adaptor Board. £9,75 extra. 



MICRO 
SYSTEMS 




Fuller Sound Amplifier Box, including 

Audio Amplifier (non-expandable) pg Qg + 80d D&D 

Fuller Orator upgrade kit- 
to m inside Fuller Box £24 95 ^^^^^KdrF^iSI^^^ 
Fuller 'Master Unif - 

including Orator, synthesiser, amplifier 

and Joystick port in Fuller Box — ~ ' qc i oqq n&n 



Fuller FDS Keyboard 
for the ZX81 or 
ZX Soectrum 



Our new advanced keyboard has the same, fine 
specifications as the FD42 system, but with a new, 
re-designed case, space bar and double-sized shift 
and enter keys. A must for the discerning ZX81 or 
Spectrum user 

SPECIAL LOW PRICE £39,95 (ina vat) + £2.50 p&p. 



ruiici ZX Spectrum 
Upgrade Pack 



1 6K Spectrum owners- upgrade to 48 K with a Fuller 
Spectrum Upgrade Pack- Complete with full assembly 
instructions. Model 2 or 3 only.£34^95(jnc.vAT) pS^p free? 



Contact us for a Special Fuller Introductory Pack 
We are looking for dealers throughout the U.K! 




Please supply the following items: 



Mail to: FULLER MICRO SYSTEMS, 

The ZX Centre, Sweeting Street, Liverpool 2. 
Telephone: 051-236 6109 



ITEM 


QUANTITY 


PRICE 


POSTAGE 


TOTAL 











































( enclose cheque/po. O 

Or. please debit my Access/Barclaycard 

Name 

Address 



Na. 



Please send me further details. I enclose S.A£. D 



VC3B3 



-^! 



YOUR COMPUTER, MARCH 1983 35 



(Eli 




O 




G 




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fiiQ®(D(c)(R)(o)OGG9QO 

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^SPACIOUS SHOWROOM 

OPEN MOM. to SAT. 
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*GOOD RANGE OF COMPUTER BOOKS 
♦AFTER SALES TECHNICAL 

BACK UP and SUPPORT 



0G70 MICRO 

Model 

ModelA(32K) 

Model B 

Memory Upgrade 

Full Upgrade 

Joysticks (pair) 

Singfe Disk Drive 

Disk Interface (fitted) 

14 inch Colour Monitor 

20 inch Colour Monitoi 

ACORNSOFT PROGRAMS (phone tor availability) 

ACORN ATOM 

Single Disk Drive (IncL FREE buffer kit) 

ATOMCALC ROM 

WORK PROCESSOR ROM 

FLOATiNG POINT ROM 

ROM Selector Board 

BBC BASIC Board 

Programmer's TOOLBOX 

SUPER TOOLBOX 

M/C CODE MONITOR/DISASSEMBLER 

PRINTERS 

EPSON MX80F/T HI 

EPSON MX80T III 

STAR DP 8480 

SEIKOSHAGPIOOA 

Printer Leads (PBC/ ATOM/ DRAGON) 

BOOKS 

Assembly Language Programming for the BBC Micro 

BBC Micro— Instant Machine Code 

BBC Micro Revealed 

Basic Programming on the BBC Micro 

Let Yogr BBC Micro Teach You to Program 

NEC '30 Hour BASIC 

Practice I Prog rams for the B BC M icro and Acorn Atom 

Getting Acquainted with your Acorn Atom 

39 Tested Progranrt^f or the Acorn Atom 

Atom Magic Book 




£325.00 

£349.00 I B I 
£359.00 ^^^^ 

£25.00 

£75.00 

£13.00 
£265.00 
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£343.&5 







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£399,00 
£349.00 
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£229.00 
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O 
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MICRO POWER LTD. 
Dept YC3 

8^ REGENT STREET, 
CHAPEL ALLERTON. 
LEEDS LS74PE 

Tel: (0532) 683186 
or 696343 



cash/cheque 
orders over £100 

All pf ices inclusive of VAX 




The Colourful 

DRAGON 32 

THE FAMIL Y COMPUTER TO FIRE 
YOUR IMAGINATION 

KEY FEATURES 

**32K RAM as Standard Expandable to 64K 
**Dtsplay: 

9 colours avaitabte. 

5 different resolutions from 16 x 32 

to 256x192. 
**Extended MICROSOFT Colour Basic 

as Standard. 

Advanced graphics commands. 

Advanced Sound 

Full Editing— insert, delete, amend. 
** Professional Typewriter Keyboard 

•*FREE 160 page 'BASIC training manual. 
**Connections for Joysticks, Printer, 
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36 YOUR COMPUTER. MARCH 1983 



coummRom 



Computer Club is here to encourage you to start your own local computer club or. If one already 
exists, to join it and become Involved. We would like to hear of anything which has made your 
club a success, or of any projects or programs you are developing. 



Simon Beestey encounters 
the micro generation gap 
and a naked Nascom at 
the West Midlands 
Amateur Computer Club. 

A NEWCOMER TO compuiing who wandered 
into one of the West Midlands Amateur 
Computer Club meetings would probably be 
struck by the number of machines present 
which have long since been out of the 
spotlight. In this respect the West Midlands 
Club is typical of most computer clubs of 
several years* standing. 

Until recently the Nascom and other kit- 
based computers such as the UK 101 held 
sway in computer clubland. Although the 
Nascom was, and is stillj available ready- 
assembled, most owners preferred to build it 
up from a kit. In the process they needed to 
develop a greater level of ' hardware and 
software expertise than is required if you buy^ 
say, a Vic across the counter. The Nascom is 
designed for expansion and dedicated owners 
often end up running CP/M and twin disc 
drives on their machine. 

When the ZX-80 appeared, as the Model T 
of home computing it introduced a new type 
of enthusiast to computer clubs. Whereas the 
kit builder had to be prepared to wield a 
solderipg iron, a Vic or Spectrum owner is 
unlikely to want to dabble inside the machine. 

A fully-fledged Nascom, circuit boards and 
wiring exposed lo view, can be an unnerving 
sight to the owner of a sealed and packaged 
mass-produced micro. Many of the new 
members at computer clubs are now more 
interested in software than hardware and 
particularly in games* 





Nostalgia versus the 
nev^ microcomputers 



Both camps are well represented at the 
WMACC- The club has been running for five 
years and has over 150 members- These 
include 40 Nascom owners as well as a host of 
Vic, Spectrum and ZX-81 owners. A further 35 
members own Pets. As treasurer Malcolm 
Sparrow explained, the club rarely organises 
talks or demonstrations but prefers to let 
members follow their own pursuits. 

Naturally interests and activities are diverse. 
Chris Kitson moved from Nascoms i and 2 to 
a Gemini board. He has written programs to 
display fast-moving three-dimensional per- 
spective views at 512 by 512 resolution by 
linking the Gemini up with a graphics-display 
processor. 

In common with most clubs many of the 



members are interested in exchanging and 
copying programs. One of the hazards of 
visiting computer clubs for a magazine is that 
the visitor is confronted with the magazine's 
readers. David Hardwick made a vehement 
but good-humoured attack on computer 
magazines in general for publishing error- 
ridden listings. He appeared to be pacified 
however by the news that Your Computer is 
setting up an even more rigorous checking 
procedure. 

The club meets twice a month on the second 
and fourth Tuesdays at Elmfield School, Love 
Lane, Stourbridge. Full membership costs £4 a 
year and as an unusual facility, members are 
ofTercd cheap insurance rates on equipment 
brought along to meetings. 



Local society nevfs 



London Computer Fair 

Thf association of London Computer 
Clubs promises fun for all the family at its 4th 
London Computer Fair on April 14-16. After 
three years at the North London Polytechnic, 
the Fair has now moved to Central Hall 
Westminster. The admission fee is £1.50 for 
adults and 75p for children. Bargain hunters 
should attend the bring-and-buy sale held on 
Saturday only. 

Gravesend computing 

Gravhsend Computer Club meets on the 
first and third Tuesday of every month at 
7.30pm in the School Room of the Extra 
Tuition Centre, 39 The Terrace, Gravesend. 
Kent. For more details ring Steve Janday on 
0474-50677. 

BBCs in Wales 

Wales, first BBC Microcomputer club has 



been formed in Cardiff. Meetings are held on 
alternate Wednesdays in the Applied Science 
Lecture Theatre of University CollegCj 
Newport Road, Cardiff. Available facilities 
include four 24in. elevated monitors and full 
audio-visual equipment. The club has more 
than 60 members and also runs a Bcginner*s 
Corner. Further information from Geoff 
Barker on Pcnarth 701023. 

The New Mills boom 

In just three months the New Mills and 
District Personal Computer Club has 
outgrown its existing premises at the New 
Mills Youth Centre and now meets at New 
Mills school on the fourth Monday of the 
month. Members' machines include most 
makes of home computer* Games enthusiasts 
arc well catered for and competitions are held 
to develop programming skills. Further details 
from John Eary on New Mills 43870. ■ 



YOUR COMPUTER, MARCH 1983 37 



FutST syres 



Starting out in home computing? First Bytes is for you. 
Just write to Your Computer with any hardware or 
software problems, no matter how small or simple. 

QUESTIONS 

What is machine code? 



'Can you tell me the 

difference between machine 

code, assembly language 

and Basic?' 

At the heart of every microcomputer is a 
microprocessor, which is really a computer 
inside the computer. The only language the 
microprocessor understands is machine code 
instructions. Each instruction takes up one 
byte — a set of eight bits of ones or zeros. 
Since a machine-code program just consists of 
a list of numbers, writing a program in 
machine code itself is tedious. 

Assemblers are designed lo make the pro* 
grammer's task easier by allowing you to enter 
mnemonics rather than the numbers 
themselves. A mnemonic both stands for a 
machine code instruction and serves to 
indicate what it does. For example the code 
248 in 6502 machine code tells the processor 
to increase one of its storage locations, the Y 
register, by ont; the mnemonic for this in 
assembly language is INY. 

Disassemblers convert machine code to 
mnemonics and can be used if you want to 
examine a machine code program already in 
the computer. 

Whereas assembly and machine code are low 
level languages Basic is a high level language 
and needs to be converted to machine code by 
a Basic interpreter or compiler. Most micros 



use an interpreter which is itself an 8 or 16K 
machine code program usually in ROM. 
When a Basic program is run the interpreter 
translates each Basic statement to the 
equivalent machine code instructions. 

Converting Basic to machine code line by 
line is both inefiicient and time consuming 
which is why Basic programs run so much 
more slowly than programs written directly in 
machine code. 



STRING 

Those dollar signs which Utter Basic 
programs represent strings. A string is a line of 
characters which the computer will treat as 




Which computer d 



'Should I buy a computer 

with a large memory, and 

which Is the best micro 

for games?' 

It is difficult to give any one feature 
priority over another without knowing your 
interests. Obviously, if you arc interested in 
graphics you will rate a high screen resolution 
above an cxtcnsiv'e version of Basic or a power- 
fiil sound generator. Like cars, some home 
computers undoubtedly offer better per- 
formance all round but cost proportionately 
more. 
As a beginner it is unlikely that you will 



need more than 16,000 bytes of memory — 
16K RAM — unless you want to store a large 
amount of data. Most of the best games 
programs fit into 16K, But figures for the 
amount of memory a computer offers can be 
deceptive. An advertised 16K of RAM rarely 
means that 16K is available for programs. 

Every home computer has an operating 
system. This is the machine code program 
which — as the term suggests — co-ordinates 
and runs operations such as printing to the 
screen^ or reading in instructions from the 
keyboard. Although the operating system is 
permanently embedded in ROM it needs vari- 
ables in RAM to keep track of what is 
happening. Consequently it reserves space in 



BEATING THE BUGS 

HOW TO CHECK ERRORS 



Few people can key in a long program 
without making any errors, Run the program 
after an hour. or two's hard typing and it 
invariably crashes. However, you can save 
yourself a good deal of frustration if you 
interpret the error messages correctly. 

Although the message indicates an error at a 
particular line usually the fault lies elsewhere 
in the program. One of the most common 
error reports occurs when a variable has not 
been assigned a value. The exact wording of 
the message varies from computer to computer 
but it will probably read something like 
"undefined variable". 

The problem here is that you cannot use a 
variable without having given it a value 

38 YOUR COMPUTER. MARCH 1983 



beforehand. If^ for example, a line such as 

100LET A = B 
throws up an error report it means that B has 
not been set earUer, Look through the listing 
and check that you have correctly typed in 
every occurrence of B in the rest of the 
program. 
Another likely message is 

OUT OF DATA 
which will be reported at a line with a Read 
statement in it. Again the error is usually to be 
found somewhere else in the program. It 
indicates that the computer has not found 
enough items in a data statement. Either you 
have left out an item or you have missed a 
comma between them. 



Syntax errors are not difficult to spot. 
Sinclair owners are fortunate that the 
computer checks each line for syntax as it is 
entered: on other machines it is usually 
sufficient to retype the line checking for 
missed colons or spaces. Most Basics will 
accept a program line without any spaces but 
there are a few exceptions and, of course, 
spaces greatly improve the legibility of a 
listing. 

These are just some of the most frequent 
problems. Other bugs are more subtle and 
harder to detect. But if you understand the 
cause of an error message it is usually possible 
to track down the error without poring over 
the entire listing line by line. 



msTtnts 



S AND TH NGS 



single unitj or siring^ unless it is told 
othenvise. If you input 

A$ = "FIRST BYTES" 
and then ask it to print AS it will print 

FIRST BYTES 
Many useful things can be done with strings, 
but string manipulation often results in knotty 
problems for the novice, so here is a quick 
explanation of string functions and their uses. 

LEN(A$) gives the length — number of 
characters — in a string. This is useful when 
you need to took at each part of a string in turn 
by means of a 

FOR N-1 TO LEN(A$hNEXT N 
loopj or want to add something to the end of 
the string. 

VAL(A$) convens the character represent- 
ing a number into that number, that is, il 
converts a string into a numeric variable. This 
is particularly useful when INKEY$ has been 

o I need? 



RAM and uses it as its own storage area. 

On the BBC the 0/S takes up 3.5K RAM 
and even the unexpanded ZX-81 has to 
surrender a hundred bytes to the O/S. 

The screen memory also consumes RAM. 
Most ' computers map the display on to a 
section of RAiVl. Generally there is a trade-ofT 
between RAM and resolution: the greater the 
graphics resolution and the more colours on 
screen, the less memory available. 

A 16K RAMpack for the ZX-81 does indeed 
ofTer a full 16K user RAM but the ZX-81 does 
not provide high-resolution graphics. 

The best computers for games at the 
moment are probably the Atari and the BBC 
Model B. Features like graphics and sound 
make some computers more suitable for games 
programs than others. But just as important a 
factor is how long the machine has been 
around and how much software has been 
developed for it. 

Neither the Spectrum nor the Vic can match 
the BBC or the Atari in their hardware 
specifications, yet the games for these 
machines are almost as good and far more 
varied. 

It takes programmers time to discover how 
to make the best use of a computer — the 
quality of software for the ZX-81 is still 
improving. 

The Dragon 32 arrived shortly after the 
Spectrum but there is a flood of programs 
being produced for the Spectrum and only a 
trickle, as yet, for the Dragon. One of the 
reasons for this is that it was easy for the 
software houses which had been concentrating 
on the ZX-81 to move on to the Spectrum, 
since it uses the same processor — Z-80 — and 
was assured of a large market. 

Most home computers are suitable for play- 
ing games on, but buyers of new machines 
should expect to wait some months before the 
appropriate software appears. 



used for input, as INKEYS always produces a 
string. Note the VAL of anything other than a 
number is 0. 

10 A$ ^ INKEY$:IF A$ = "'THEN 10 
20 A = VAUA$hlF A<1 THEN 10 
This rejects anything other than a number 
from one to nine. ASC(AS) gives the ASCII 
code of the first character in the string. This 
can be used to select a group of adjacent 
characters, such as the numbers one to five. 
20 A = ASC(A$):iF A<49 OR A>53THEN 10 
STRINGS(N,A) forms a string of length N 
made up entirely of character A. A may be the 
ASCII code for a character or the character 
itself in quotes. Both STRING$(10,65) and 
STRINGS(10,**A") will form a string made 
up of 10 letter As. 

String slicing is carried out by three 
functions: LEFT${AS,N) gives the first N 
characters, RIGHTS(A$,N) gives the last N 



I could 
do that 



Travel agents' windows often feature a 
moving advertising display. First Byters 
can win £15 by sending us a program 
moving up to 10 characters across and 
down the screen, starting at the top, 
passing left to right, feeding into the line 
below, then scrolling backwards and up 
to the top. We are looking for simplicity 
and elegance. 



characters, and MID$(A$5M5N) gives the 
middle N characters, starting from character 
number M. If 

A$ = 'THIS IS A LONG STRING" 
then LEFT$(A$,4) = **THIS", RIGHTS 
(AM) = "RING'^ and MIDS (AS,I1,4) = 
"LONG". The line 
FOR N-1 TO LEN{A$}:B$ = MID$(A$,NJI: 
NEXTN 
will make B$ = each character of A$ in turn. 

When adding strings the second string is 
always put after the first string. 

A$ = "L0NG":8$ - "STRING":« - B$ + A$ 
will make C$ = **STRINGLONG" and not 
"LONGSTRING". Note that when adding 
strings you often need to add spaces as well. 

C$ + A$'f " "-fB* 
gives "LONG STRING". 

STR$(A) is used to convert a numeric vari- 
able into a string which can then be added like 
any other string. 

A = 1:D$^STR$iA) + C$ 
gives "1 LONG STRING". 

To insert into a string it must first be 
divided into left and right portions at the 
appropriate point, and the various pieces 
added back together in the correct order. 
E$ = "VERY'*:F$ - LEFT$(D$,2) + 
E$ + " " + RIGHT$(D$J1) 
will now give "1 VERY LONG STRING". 
This type of string manipulation is important 
in text editing, and also often in sound and 
graphic functions which are handled as 
strings. 

String searching is carried out by 
INSTR(N,AS3S) which will search A$ for 
B$5 starting from character N. If B$ is not 
found the result is 0, otherwise the position at 
which B$ starts is returned. 

One of the most straightforward uses of 
INSTR is in checking for valid entries. All 
valid keys are included in GS^ and each 
INKEYS value is compared with this. 
10G$=^"ABCDEFG" 
20H$ = INKEY$:IF1NSTR(LG$,H$> = 1THEN10 



ASC II CODES 



Every ch.^racter on the keyboard is repr- 
esented by a code and when the computer 
stores a character, it stores the code in a single 
byte. Almost all computers adopt the same set 
of codes — the ASCII set — pronounced 
askey, as in Arthur Askey. A notable exception 
is the ZX-81 5 which uses its own set of Sinclair 
codes. 

Since one byte can hold a number from to 
255 the set can contain up to 256 codes but 
only those for the keyboard characters are 
standard. The other codes are usually specific 
to each computer and could be used for user- 
defined characters or predefined graphic 
characters or as control codes. 

If you type in and run the program you can 
see which codes stand for which characters, on 
your computer. The Basic keyword CHRS 
generates a character from its numerical code. 
10 FOR N= 32 TO 255 
20 Pmm N, CHR$(NJ 
30 NEXT N 

You will notice that the For-Next loop starts 
at 32, This is because codes to 31 are usually 



reserved for control characters. When the 
computer encounters one of these instead of 
printing a character it carries out an 
instruction. Control codes can be used to tell 
the computer to do such things as move the 
cursor up, clear the screen or change the 
colour. 

Using CHR$ with control codes can be very 
useful for printing a number of characters to 
the screen quickly — enabling you to speed up 
games written in Basic considerably. For 
example, if 8 is the code for cursor left and 9 
the code for cursor down, 

PRINT "EE";CHR$(9);CHR$t8);"E" 
would print one '*E" on top of the other. But 
it is more useful to insert control codes in a 
string firstj as in: 

A$ - "E" + CHR$(9) + CHR$(8) + ''E" 
followed by PRINT A$. 

This is a rather simple example. To discover 
what further uses control codes can be put to 
look them up in the ASCII tabic in your 
manual and try experimenting with PRINT 
and CHR$. ■ 



YOUR COMPUTER. MARCH t983 39 



EaR1,Y ORICS were plagued with a shaky 
display. Now the problem has been solved 
with an Astec modulator but the Oric's 
picture is still not as good as the Spectrum's. 

Both machines exhibit dot-crawl. The Oric 
has two modes of operation. Text, which 
allows the user more of the 16K for Basic 
programs — 12,288 bj^es — and Hires — 5>120 
bytes. Aaual bytes free for Basic programs arc 
calculated by reference to the Oric memory 
map. 

The Spectrum only has 8,846 bytes free but 
can mix text with Hires without resorting to 
calling ASCII codes. The Oric picture always 
retains a black border and this can be a 
disadvantage. 

Ink and Paper 

If you wish to provide the effect of a green 
playing surface^ the Spectrum permits a green 
or any other colour border. Both systems use 
Ink and Paper commands, although the global 
effect on Spectrum is only achieved after a CLS 
command. The colour resolution of the Oric> in 
Hires, is greater than the Spectrum. 

The Oric uses a six-by-eight character cell 
size which produces noticeably lower character 
definition on a television display; the Spectrum 
has a eight-by-eight character cell. 

The Spectrum Beep command has always 



Spectrum on /eft Oric on right 



Test f. Array loading. 

^T997e«7797697»«74.«T39"7a^71Q7©»e 
'a9eS9e7g6696SQB4.983g&a9eiQ&QQB90 
S09S795G9589S49539S206i9S094994.tt 
04794iB0iiS9AA0A3«4 294.3.9AO93093SQ3 
793a03B934.933933931,«3d9a99?eQS7Q 
2S93B924.9a302S921.9a«9190XeOr70ie 
9 184 14.9 139 129 1 19 lO 9«99eeQQ 79069« 

3904.903902901 ^ ^^.^ 

9e l9Q&9039a490ll9OB9a79009Ca^':» 109 1 
19 129 239 149 1S9 189 179189 1993092 19 
22923924928928927928939930931932 
93 393493S93893793S93994094 194294 
39449489489479489499509519829839 
54988986987958989980981982^83984 
98898898 796098997097197297397497 
5978977978979980981983983964 9889 
889 8 7988 9B999099 ^ 993 993^ 94 99flt998 
d9 79999991000 



3 DXH 6I10O0> 

3 rO« »-l TO 100* 

4 LET l>(lO0i-a>-* 

5 NEXT A 

© aO 5U8 30: PPINT 

7 Lirr c«o 

8 FOR mmX TO 99 

9 Zr t>iAf >if(**X> TPiCH QQ 5Ue 
& 

le NffXT « 

11 XF ?<>© THPN GO TO 7 

13 oo sue 30 

13 8rop 

20 FOR a*l TQ lOO 

31 PRirrr ^^f«) ; 

33 N&.VT Ji 

30 LCT <*«fr(*> 

31 LCT t>(»> «it>««4>4> 
3S LCT & (441J *ta 

33 I.CT C*! 

34 RETURN 



Test 2 Drawfng circtes. 



3 FO» »«60 TO 3 STEP -& 
3 riRCLC 1^*5.^3,4 




been limited in use within a Basic program, 
being a single channel. The Oric uses the 
AY- 3-89 12 sound chip which provides three 
channels capable of producing a multitude of 



SPEED 



i ojrtBtieeej 

5 N£XI 

6 SOS4iB20iP»fKT 

7 C-^ 

9 ;f&C^>>8CAtl>lKEH aOSU8J0 

II rpcoencN 60T07 

|7.50SUB2a 



13 STOP 

^2 NEXT 
25 RtTURW 
30 0-81A) 

32 etAM l-D 

33 C-1 

34 RtTviRN 



Oric 

Time to load array : 15s, 

Time to sort array : 300s. 

Space occupied by program : 225 bytes 

space occupied by variables: 5,036 bytes 

Spectrum 

Time to load array : 13s. 

Time to sort array 285.6s. 

Space occupied by program : 339 bytes 

Space occupied by variables : 5,037 bytes 



1 HIRES :ClJ?fSET 120, le 

2 FO«!fi"007O2STEP-2 

3 CIRCLE^*, 3 

4 Ntx? 



Spectrum : 31.2s. Oric ; lT3s. 
Unfortunately the Oric "circles" are 6.14 wide 
by 4.87 high. 





Test 3. Drawing boxes. 

4. DPAU • .0: ORAU C^ <»-e0» 
^ MC>T 4 

Spectrum : 4.51s. Oric ; 6.1s, 



DR 



» HlftES 

2 CURSET2,2,1 

3 F05W-23ar084ST£P-4 

ftftUe,C82-A>,l 
5 NtXTA 



the: 

ORIC 



Even ice-cool Cllve Sinclair 
is feeling the nail-biting 
tension. Kathleen Peel asks 
whether the proven virtues 
of the Spectrum and 
nnassive availability of 
software will be enough to 
stave off the challenge of 
the Oric which 
appears to offer 
more for 
£25 
less. 




difierent sounds^ plus white noise. The oddity 
of it all is that the Spectrum is rather quiet and 
the Oric*s buih-in commands of Zap, Ping, 
Shoot and Explode are raiher noisy. 

Both keyboards have a calculator feci. The 
Spectrum keys are reasonably large and the 
"feel** can be improved by typing Poke 
23609,50. This provides audio indication of a 
key being pressed. The Oric keys are much 
smaller and spaced slightly closer together, 
but at least the Oric has a full-size spacebar. 
The keyboard plays a more important part in 
using the Oric as almost all words must be 
typed in full and therefore, require the user to 
be accurate in typing commands. 

Oric Basic enables the user to use integers 



40 YOUR COMPUTER. MARCH 1983 



SHOOT- OUT ^ 
V. SPECTRUM 



} 


^^^^^^^1 ORIC-l ^M 


1 




^^^^^^^^^^^^^^^^^^^^^^^^^^^^^1 




1 cm A SDFGHJ KL:'" «•.««. 


BABpBHH 


1 !K lit III *ll lit ]l 




- t 


♦ — 


^^^^^^ m m m mr i^^^^^H 


1 




and does mean that the Oric memory require- 
ments are smaller and that more can be 
packaged into a Basic program. I suggest you 
took at the program listings carefully; if you 
are new to home computing, the fact that the 



Spectrum spaces the text for easy interpre- 
tation with an excellent line syntax checker 
may be crucial. If^ however, you have already 
mastered the fundamentals of programming, 
then you may prefer the additional potential of 
the Oric, 

Relatively bug-free 

It is worth bearing in mind that Spectrum 
Basic was developed on the ZX-80 and is now 
relatively bug-free. Even the IBM Personal 
Computer had some errors. The Oric may 
sufier in so far as it is a substantial step away 



from Microtan Basic, Tangerine's old Basic. 

The Oric limits the length of a line of Basic 
code to 77 characters. At 75 characters, the 
first of three warning Pings is emitted, on the 
78th character the line is deleted. There is no 
line-length limit on the Spectrum. 

Oric*s editor is worse than the Spectrum's. 
Edit X brings line X to the bottom of the 
screen. Typing Control A over characters in 
the line writes the characters into a duplicate 
line which on pressing return replaces the 
original line. Cursor keys delete characters, 
while typing a character then backspace cursor 
inserts characters. Unfortunately the amended 
line is not visible while changes are being 
made. 

Saving and loading 

Saving and loading is not without problems. 
The Spectrum has a printer which is a low- 
quality, low-cost machine and will produce 
screen dumps and listings very quickly. 

The Oric uses a Centronics interface which 
operates with Strobe and Acknowledge only. 
This should allow you to use a wide range of 
printers but it has not provided satisfactory 
results with the printer I used. 

The Sinclair manuals have been gradually 
refined and are now very good. The latest Oric 
manual is a vast improvement on the 
provisional offerings sent out in December 
and January but is still not as comprehensive 
as the Spectrum manual. 

Last summer some micro enthusiasts had to 
wail 20 weeks before the Spectrums they had 
ordered were delivered* It is early days yet but 
if demand is high as Oric has stated, I wonder 
what deliverv time scales will be achieved. 



CONCLUSIONS 

■ When comparing machines, it is 
always assumed that any innovative or 
exceptional function of one machine 
shows up as an inadequacy in the 
other. This is not the case, both of 
these machines are or will be excellent 
value for money. If you have £125 to 
spend, then the Spectrum is perhaps 
ideal for the beginner or someone who 
has outgrown his ZX-SI or ZX-80 and 
wants a machine now. The Oric is 
likely to be of more use to somebody 



who already knows a little about 
computing and who will be able to 
break the syntax barrier. 
There appear to be many problems stilt 
remaining with the Oric's ROM, and 
perhaps the interface control. It is too 
early to talk about an extended version 
of Oric Basic when this particular ROM 
has not yet been fully debugged. It is a 
great pity as the potential of the Oric is 
far greater than that of the Spectrum, 
and this will obviously appeal to the 
more technically adventurous micro 
enthusiast. 



Missing commands include ACS — 
Arcosine — and ASN — Arcsine. They 
can be evaluated using Cos Sin and 
Arctan. Other useful commands not 
implemented include Copy, Verify, 
Merge, Flash and Double: these can be 
simulated using control characters. 
There are no disc file-handling 
commands which may mean a new 
ROM required ^ la BBC. 
It is important the Oric replaces the 
EPROMs in the early machines 
delivered as soon as possible and free 
of charge* H 



YOUR COMPUTER, MARCH 1 983 41 



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Mail or telephone order 
Barclaycard or Access 
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Applies to orders 

MICRO MANAGEMENT March'sTonS 

Micro Management 32 Princes Street Ipswich, Suffolk. Telephone: (0473) 59181 



Only defective or faulty goods 
may be returned. 



YOUR COMPUTER, MARCH 1983 43 



Tandy*s new four-pen Colour Graphic 
Printer could have the same dramatic cficci on 
printing as the change from black and white to 
colour screen displays has had on computing. 
It is a direct descendent of the CE-150 2.25in. 
colour printer produced by Sharp for the 
PC- 1500. 

The prinier, complete with RS-232 and 
Centronics inierfaccs> costs £149 including 
VAT but not including any connecting cables. 
It comes with a power supply, operation 
manual^ three black pens, one each of blue, 
green and red, and a roll of plain paper 4.5in. 
wide and 180ft. long. The machine is a healthy 
8.5in. square by 3in, high and weighs L751b. 
It is coloured silver-grey, with a black top 
cover which is raised to gain access to the pens 
and their holders. 

The printer can print either 80 or 40 
characters per line. The ASCII character set 
from code 32 to code 127 is implemented, 
although unfortunately there is no pound sign. 
A switch marked special characters provides 
for Japanese script. 

The characters are not produced by a dot 
matrix or burnt into aluminised paper. In 
either case, present technology would not 
permit 80 characters within a space of a little 
over 3.75in. The characters arc formed in the 
machine's internal ROM and written on to the 
paper using ink pens. The effect is similar ro 
high-quality type-written text. Except for the 
lack of proportional spacing of characters, and 
paper width, the performance is as good as 
many professional printers. 



The printer has two modes of operation, icxi 
and graphics. The Graphics mode permits 
character size to be varied from 80 characters 
per line to one character per line, in 63 steps 
retained on return to text mode. Characters 
can also be rotated in 90*" steps. Also available 
is the facility to draw 15 different types of 
dashed line. Colour can be changed and a 
return to text initiated with very simple 
commands. 

Axes are specified in terms of X or Y with a 
defmed step and interval. The step is a 
multiple of O.OOSin. between 1 and 999, 
positive and negative, and the interval, the 
number of repetitions of the step, is between 1 
and 255. 

The effective X-axis resolution of 480 steps 
and equivalent vertical resolution draws 
convincing circles, without annoying steps on 
the edge. 

The printing speed is a slow 12 characters 
per second. At present screen dumps of 
graphics are not possible. 

The machine is opened by undoing five 
screws in the base and releasing four locking 
tabs to release the top moulding. The base 
holds the print and feed mechanism at the 
front. The paper drive is friction -fed by a full- 
length rubber compound roller and side 
pressure rollers which also prick the edge of 
the paper at 0.156in. steps. This gives the 
effect of tractor drive and has the advantage of 
providing the Y axis with a quoted accuracy of 
one percent coupled, with a repetition 
accuracy of O.OOSin. 



The PCB is screened from interference and 
the major integrated circuit components are 
encased in a screened box shaped around the 
parallel input/output socket — very pro- 
fessional. There is a large heat sink down the 
right-hand side at the rear. 

The top moulding of the unit houses the 
power switch, serial input/output socket, and^ 
power socket at the rear. A small PCB 
houses the power indicator lamp, the 
paper-feed and colour-select push 
buttons. Fmally, housed under 
the mechanism cover is the 
manual pen-change switch. 
The top cover lifts to 
expose instructioQg 
labels, one 
concerning 
pen 



CGP-115 LISTS IN 





44 YOUR COMPUTER, MARCH 1983 



REVIEW 

If your listings are listless 

and your printouts are 

plain, the CGP-115 

could be what you 

are looking for. 

Kathleen Peel 

checks it 

out. 




replacement and the other noting how to look 
after your primer. 

The 50-pagc manual is well laid out and 
clear, but there arc some omissions. The 
appendices provide some Basic programs 
which produce pic charts, sine and cosine 
curves. 

It is surprising that there is no indication of 
the connections on the four- way DIN socket 
masquerading as an RS*232 interface. Only 
pins 2, 3 and 4 are wired. Table 1 gives the 
connections. The serial interface operates at 
600 baud with no parity and two stop bits. 

The parallel interface is via a Centronics- 
type plug but the only connections used arc 
busy *- Pin 11, strobe — Pin 1 acknowledge — 
Pin 10 and the data lines. 

Loading the paper was initially a bit of a 
problem, A protrusion in the centre prevented 
the paper from being entered into its loading 
slot completely, and so take up, by pressing 
the paper-feed button, could not take place. 
The answer was to cui a strip of paper 6in, 
long by lin. wide and load this into the slot 
close to one edge, such that it could be fed 
through by hand. The strip was then slid 
across into a central position and the full paper 
width loaded over the top of the strip. As soon 
as take up was established the strip was 
removed. I only used this procedure twice as, 
whatever the obstruction was, it disappeared. 
Loading the pens was straightforward if a little 
fiddly. Neither operation is likely to be 
required very often. 

(continued on page 481 



COLOUR 



ORIC--TANDY CGP-115 

Centronrcs Interldce 



SPEEOSLOC CABLE RS 467- 28S 

nOUNTIHG SOCKET 20-WAT 

Above: sample Oric/CGPffS printout. 



73 



LPftiHX'-ftm, 2m'' ivgn twe noon 

LfftlNr''H»Cl,23, l«''!«£T1 HOmi AKIS 
LPR|Hr*'S2'^.R£n CHftR Sllf 
LpftJHrTl';«fn IH n[D 
88 LPftINr''C»'';RCn i«fTE LErr SIDE 

m LpftiHfrviijiaiREfi pas pen 

92 tPPJHfPa^LE'-REn yRIfE UCRT 

w LpRiNfmai-^'i^n pes Ptn 
m LPRiwr-M' ;^n mtiiL right u^y 

S? LPfHHr'C2-;«l£n IN QUEEN 

m LpfUNr'p iseo'-ttcn title 

•30 LPPIHT'CI" 

179 LPRIHT''r«,»'^ 

t3i LPRINT'D2«,73'- 

200 LPFIHT'D^e.M* 

210 Lffl]HT''OJM|lM'- 

2Sf$ LPUIHT'Ci' 

233 LfRlNT'S«' 

280 LfftJHTr«,C# 

20) FOR?(-lTOeiLPH|Haii«XfX 

202 LLIST 

20^ END 




1-983 



Above: typicat SO-character pnntout. 



8"«$^8c^ C3*+,-./0123456789: ; <=>?eABCD£f G 
HIJKLnN0PQRSTUUWXY2[\]>^_<abcdef9hUk Imno 
pqrstuuuxyz{ ! }^B 

Auto -test character set. 



Function 




Tab/e f, Pourpin socket terminations. 





Printout 


Length/£ 


Sq. ft./£ 


Sinclair 

Amber ^ 
CGP-n5 


27.2 
129.4 
112.8 


9.1 
24.3 
42.3 


Table 3. Paper usage running costs. 



10 REM LINE SAMPLE PROGRftn 
20 PRINT, CHR$C 18) 
30PR1NT,"L3" 
40PRINT,"J480,0" 

50PRINT,"A" 

60 END 

Sampfe BBC/CGP 115 printout. 



YOUR COMPUTER, MARCH 1983 45 





fo. 




. TECHhOLOGY FROM ORIC PRODGCTS INTERNATIONAL 



-^vk.^-.: . ^^^^.: 



Hie 



__ 16 colours 
professional ke^oaid 
_ full graphics \^^^^ 
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with every 

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Choice of 16K RAM or massive 48K RAM 



Ergonomic keyboard with 57 moving keys 



28 rows X 40 characters high resolution 



Teletext/viewdata compatable graphics 

# 6 octaves of real sound plus Hi-Fi output 



Centronics printer interface and cassette port 



# Comprehensive user manual 

OPTIONAL MODEM OFFERS COMPCJTER PHONE UNK FOR: 
• ELECTRONIC MAIL • TEUESOFTWARE • PRESTEL 



THE REAL 

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99 

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COMING SOON, TO COMPLETE YOOR SYSTEM: ORIC MICRO-DRIVE DISCS & SPEED PRINTER 



i FOR HOME: The ORIC-1 is the professional alternative for home computing. 
Superbly styled, the 57 key layout is based upon computers costing many tim.es more 
than the ORIC , and will help the whole family to learn and understand computing, 
right from day one. The ORIC incorporates an improved version of Basic 
— for ease of programming and use. For the enthusiasts the computer has laser ^^ 
zaps, explosions, etc. pre-programmed for games use, with Hi-Fi 
output for incredible effect The communications Modem will 
allow 'Telesoftware', message sending, and Prestel use. ^ 

I FOR BUSINESS: The ORIC-1 is the answer to many 
y to day problems. Software is becoming available for x ' 
payroll, accounts, stock-control, and many more systems ^ 
G help your day to day business organising and control. ^ 
I addition, the ORIC COMMGNICATIONS MODEM will . ^^ 
vyou to access up to 200,000 pages of Prestel 
...Simation, to send and receive 'electronic mail', ^ 

> book hotels, and flights (and pay for them) and to \ 
^ at the latest stockHj|a|jket and share indexes. 
' In short ti^^PlVRlTmust for all businesses 
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^ HOW TO ORDER YOUR ORIC-1: By phone: 

Just rinSpur telesales number Ascot (0990) 27641 . 



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ACCESS IBARCLAYCARD - AMEX - DINERS. 
(Please allo\^^8days for delivery). 



• «?Copyright ORlC PROlXlC rS INTERNATIONAL 1982 



i continued from page 45) 

When the printer is switched on, the pen 
carrier traverses to the left-hand edge and 
rotates the pens to ensure thai holder number 
one is in the top working position. The printer 
then draws four boxes produced sequentially 
by the pens in holders U 2, 3 and 4, This is to 
ensure that the user is aware of any dried-up 
pens. 

Pressing the paper-feed button at switch on 
sets in motion a self-icsi procedure thai also 
prints the character set in the four loaded pen 
colours. 



CONCLUSIONS 

■Tandy's new printer will transform data 
presentation and allow the computer 
to interpret results fully, for ease of 
reading, varying colour, indentation, 
and print size as necessary. 

■The graphics capability provides for 
considerably better resolution that 
available to the majority of micros. The 
lack of a screen-dump facility is likely 
to be temporary as users will soon 
develop software to produce screen 
dumps in colour. 

■This high-quality printer can only be 
faulted on paper width, and slow 
speed which may make it unsuitable 
for word processing. ^ 




Tafofe Z Comparison of machines 






















Characters 


Paper 




Printer 


Basic 


Accessories | 




- 


















Colours 


line 


sec 


Type 


Width 
in. 


Length 
ft. 


Size 
in. 


Cost 
C 


Paper 


Rib- 
bons 


life 
















5.5 










Sinclair 








Metal- 






X 




11.95 






Printer 


1 


32 


50 


ised 


4 


65 


2.9 

X 

1.9 


59.95 


for 
5 




















6.3 










Amber 














X 




3.40 


2.00 


3x 


2400 


1 


24 


17 


Plain 


2.25 


88 


6.3 

X 

3.1 


89.70 


for 
5 


Ribbon 


88ft. 
rolls 
















8.4 














80 to 










X 




3.99 


1.69 


825ft. 


Tandy 


4 


lin. 


12 


Plain 


4.5 


150 


8.6 


149 


for 


for 


each 


CGP-11S 




63 
steps 










3 




3 


3 
pens 


pen 



NEW 

SPECTRUM 

SOFTWARE 



TRrVNSYLVANlAN ItlWKR 

\n this spintJ (:hillin*» iutvnnlum yoir oxijlon* Oninf Dracul^rs dark 
lovvor from lliu clisninl (lung(K)!is to tho t(!rn(yiug lop! Discovtir his 5(K1 
HMHii nwvAv, \\\{\\ its ini:nHlil)ly sptniltunilar nKJving thnMMliuKUTsionnl 
gniplncs. VVnich oul lor ihn svvoopin** v<nu|)ircj l)als as ynu liy to rid 
tlio world oF this Transylvanian ttUTor! (lonihinos an advtniluni uilli a 
maze with a fast moving grapliic action gamii! A now ma/i* nvtuytimc?! 
With a lull \savn* roulitie for use during thn davlighl hours! 48K 
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EVEREST ASCENT 

Stake your claim to the; top of the world in this demanding vertical 

a(!venlure in which you aim to niach the summit of the vvorld*s 

high(jsl peak. A (:(jmi)U?x game; of strategy and sunival. 

For IB or 4HK S|KH:lnnn (For the IHK Spectrum we have divid(Hl 

liveit^sl As<:ent into tTxciting parts to give you an adventure as 

comijl(!x as the 48K vei'sion) 

Hi & 48K SPKCI KlIM Oi.50 



Richard Shepherd 
Softn/are 

FREEPOST (No stamp required), 
Maidenhead, Berks SL6 5BY. 




Promotion's the name of the game in 
'SHIP OF THE IJME' - An adventurous management game. 
Fearlessly balde your way up Uie ranks.., encounter enemy fleets... 
sm*vivc mutiny, fever and famine... endure fog, fire aiid lliirsi,„ then... 
when you think you've done well... rush home to Fort for promotion! 
t6K SPECTRUM £4.95 48K SPECTRUM £6.50 

MULTI FUNCTION CASH CONTROLLER 

'I akes care of your Home Budgeting, Hank Account, Standing Orders, 
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stx;ret password. A budgeting bargain for only £10. 4aK SPECTRUM 

SUPER SPY 

A complex adventure for the 48K Spectnnn incorporating a Rili 3 D 
maze. The many sections of this game ensure that you arc entertained 
for hours if not davs. Full *savc* facility. 
Only £6,50 48K SI^KCTRUM 



ORDER FORM Please send me 

16K E\wt!St Asii^tH 

46K 'rmiis>'K<uiian ImuT 

1(>K 'SluiJ ii tln^ liin!* 

4aK 'Ship of tJw line* 

4«K fkifXT Sfy 

48K Mijltifiinctk«i Ca^i OjittitJjLT 

I enclose my cheque/Postal Order for£ 
payable to fiichard Shepherd 



Name 

Address 

Machine 




ByhrstOassPost 
On Quality TDK 
Cassettes 



K Memory 



48 YOUR COMPUTER. MARCH 1983 




7' •■ ■ 




OniCdMC^Q (A&B) 

SPACE ADV£nTuR£ (Mod* I) M^chtre dmc ■ (32KJ 

Our btti v«l'ii>9 ^»nw tof th« Atom now re^riit«r> *fid ♦Ah«afvctd tof tH# B 8.C 

lolri^mq mixture of Sp*ce rnvidtfi, Mi2* *»id Adwtrttwr* A« in o^e 9*nrtt £$ 

Ml DOLE KINGDOM (Mod* 7» Bmk & M^hiM Coi»» 

Onyft*! f«*» t<"K *d*«"lufp v*nh owf 300 room* to liod 4^d v«p*o««. F»a»** (<" ♦vo'd'J 

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SPACE INVADERS (Mo^ 5| MKhift*Cod«. 

fmX #<liO«v. luH-f«*luf» wrriiO^ of thit pOpvUr 9JfTv« Out\1«r>din>f l»qh reu>twtiort co'our 

gr^phtct pM touted €B 

REVERSi irtd GOM0K£ (Mode ^J Mjctitn* Code 

R«lponi« tim« undM Ofvf vcco^d to< lh« fit it i ltir*H. MjAy f^atufei mctudtng ^rK^h^t 

boa'd, pfoblem toMn^, elt Both ^it/r^m *ft v*»y *b*i>*b'rt9 *ftd chjiief^girvg CS 

GAMES TAPt I (Mod* b) M«h.rt#Co<J* 

Moving W«H B'taktHit^ Sf^e jnd Hunt m9 Int moving ^ddKtivt 9»mtf, v«iy colouitui 

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MICRO MA^ (Mod* 2} Mschit*^ Cod* ■ (32K) 
F»t mcw»A9, *xc«ll«nt co»ovt qr^tkhiit wilK $oaAd. 

* NEW * Word procmsor package only £t9.% 

Woltef^ in m#thint <od« »0' *5»««tf 4rti> **f«tii*ly t*iy 1o ui* wtlh full on.vc*e*n td't*o^ 
^d lufttticition (fnore u*eM *nd f»OiMtrfM» iKm j t«>il edilOi-J. imert. del«lf. my**. 
copy. v**r*l)l# Ub wtt*n$. m4«9iAt pU/\ m*ny mo»» ff^lum Couplet* witK >mtructtoo 
mintj4l S.A.C . loc furth«r dtUtii. 

A* I pro^rdfns supplied ©« Quality C-JV t4>**tl** All piitet **e itHluVif*. no tutrix 
Buy «ny two c»si«tt«i jnd d«dw<t 1 1 from toul SAX fot C4i»lo»>« 

4T0M 

Softwv* Jt» tvtiUbt* S^Kt Advvniu'*, Sr-Jif ln»*iJ»«. Ai. St>il<» Only U »«:h 
SW E. fo' ««!*ih of ow fuH t 



PRO SOFTWARE 



OIlEHDSSSHSElli]®®!! 

DnnDii]E[G](i]S[NiDnnn 

BBIIlSnEESlMlStRKDiA]® 

nnnasamBDEBiann 

I MAIL OWPEROWLV 



PRICE BREAK-THROUGH ON 
EXTRA MEMORY FOR ZX81 I 

TheNEWEcDnoTBchlBKRAM PACK 

add$ 16-tlmM more mmiory to your ZX81 at a budgot prioal 



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guaranteed - neat and compact, 
fits snugly to eliminate wobble. 
Compatable with ZX Printef . 




ONLY £19.95 1 

plus £1 .SO post & packing 
to anywhere In the world 





Full refund if not fuHy satisfied - simply return within 
14 days of purchase. Allow up to 28 days for delivery. 
Fill in the coupon below and send with cheque or P,0. 



To: 

EconoTech. 30 Brockenhurtt Way, London SW16 4UD 

Please send me .... 16K RAM Packs ® £19.95 each, 
plus £1 .50 post and packing . 

Name 

Address .•.-.- 



campbe 
systems 



THE VERY BEST IN MACHINE CODE 
FOR THE ZXSPECTRUM & ZX81 



SPECTRUM 16K GULPM AIM ;,me of the ■ man- variety 

With 15 mazes, 4 chasers, laser detefic**, 9 grades, 9 $peed$, demo mode, choice 
of joystick control. "An extraordinarily good program" raves Boris Allan for 
Popular Computmg Weekly, We think you will agree. £5.95 

SPECTRUM 48K M ASTERFILE busfne«/dom«.ic filing 
and reporting system. So flexible that it is equally usable for yoiir mailing lists, 
catalogues, stock cornrol, text extracts applications are endless. Fully user- 
defined daw and repon display formats, dynamic variabfc-length file, records 
and data items. Fully menu driven with powerful search facilities, sorting, total/ 
avera9e, update, multiple independent files, printing. Yes, vve aim to support 
microdrive when Uncle delivers. Nearly all the 8K we use is machine code, so 
yoM get 32K per file. Comes with example file and 2 a-page manual. £15.00 

SPECTRUM 16K SPDE Disassembler and Editor, as used by 
.oiher 2X professionals, and we, used it to develop the above* £5.95 

ZX81 16-48KTHE FAST ONE « ,he pre*ce«or to 
MASTERFILE and is in use all over the world now. Specification is very similar 
toMASTERFILE. £12.00 



2X81 16KGULP2 



almost identical spec to GULPMAN. €4.75 



AH progran^ supplied doubhrecorded and mailed tst cfois by return. Prices 
include VAT md postage within Europe. SAE for Ml list. 



CAMPBELL SYSTEMS 

(Dept.YC) 

15 ROUS ROAD 

BUCKHURSTHILL 

ESSEX IG9 6BL 

ENGLAND 01504 0589 





From Warp 
Factor Eight 




Lift'Offinto 

'83with HI-STAK 



makes your computing easier, faster, 
more reliable, fess exhausting and simply 
more enjoyable. 

angles your computer neatly to the 
correct ergonomic position for the most 
efficient keyboard operation 

provides extra ventilation for hot ZXSl's 
and Spectrums. 

instantly applied. 

styled for 83, adds that professional took 
to your set up. 

precision injection moulded in quality 
ABS, non scrntch - non slip base. 






ZX81 

SPECTRUM 

VIC20 

TRS80 

NEW BRAIN 

JUPITER ACE 

Eta 



Order form. Please send nf>e ^HI-STAK set(s) (at £3.95 per 

set). I enclose cheque/P:0. foe 



Name 



Address 



Post code 



To: Warp Factor Eight, Dept. YC. 

6 Pelham Road, Braughing, Ware, Herts. SGI 1 2QU. 



YOUR COMPUTER, MARCH 1983 




If you are all at sea when it comes to choosing 

programs for your BBC Micro don't gamble — 

consult Peter Connor's software guide. 



BBC SOFT 



SoiTWAKi- iORlhc BBC Micro is still pouring 
down like invading aliens in a video game. 
Mosl of it is improving rapidly in 
presentation^ if not originality. Nearly all ihe 
games reviewed here have good graphics and 
sound, and nearly all arc ilic close rclaiives of a 
standard arcade game. Like racehorses, arcade 
games produce many offspring; "by Defender 
oui of Invaders". Unfortunately not all of 
these games are thoroughbreds. 

Superior Software has produced several 
games, all based on old favourites. The most 
interesting on oficr is Centipede^ apparently 
the only available version of this popular 
game. You have to try and destroy a fast- 
moving and very unfriendly centipede which 
snakes down from the top of the screen, There 
are other hostile creepy-crawlies, including a 
spider which menacingly bounces up and 
down above or on you. Visually this game 
compares well with the arcade version, being 
colourful and clear. Un fortunately, it is not 
possible to fire as rapidly and this can lead to 
many an untimely death. 

Invaders and Galaxians are also produced by 
Superior Software. These two games, as their 
names suggest, are standard issue. Both, 
though, are we 11- prod need, with colourful 
graphics, responsive controls and the usual 
bunch of extra-terrestrials. 





Space Fighter^ from the same company, is, 
advertised as a mixture of Defender and 
Set amble. However, it is not as exciting or as 
complex as cither of these games. There is a 
curious efleci to the display; you seem to be 
underwater spearing fish rather than blasting 
baryons and mutants in the lonely sky. 

Alien Dropout, again, from Superior 
Software, has nothing to do with spaced-oui 
hippies. Instead, in another variation of the 
Invaders and Galaxians theme, you are 
attacked by killer moths. Do not be fooled by 
their placid purple appearance — these moths 
are out to get more than the clothes in your 
wardrobe. 
Alien Dropout is not as fast or as furious as 
Invaders or Galaxians, but it does 
have a certain homely charm. 

The last program under review^ 
from Superior Software is Fruit 
Machine. This gives you a fruit 
machine on your screen. You can 
nudge or hold, collect or gamble. 
It is just like the real thing — 
except, of course, that there is 
no money. The program gener- 
ously gives you a credit of 20 to 
begin, and when it has cleaned you 
out you can start all over again. It 
is difllcult to image who this 
program will appeal to; are there 
fruit machine addicts who play for 
the sheer fun of it? If so, then this 
is their program. The graphics are 



very good and with a little imagination you 
might be able to convince yourself you are in 
I.as Vegas. Perhaps it will help to wean 
compulsive gamblers. 

From Program Pow^r come Alien Destroyer 
and Laser. Both have good, colourful graphics 
and a range of skill levels. The first is an 
Invader-style game with a variety of bombs 
and attackers. An engaging detail is the little 
yellow man who leads you back to the starting 
position when you have been destroyed. 
Another bonus for connoisseurs is the Battle 
Report you receive after each gatne; 
percentage of hits, number of torpedoes fired, 
and so on. Laser is a version of Missile 
Command, and quite a good one. All the 
familiar features are there and the player has a 



50 YOUR COMPUTER. MARCH 1983 




SURVEY 

WARE 

wide range of options — perhaps loo many 
unless you arc as CamUhu with the keyboard as 
a toucb-iypist. 

The new version of Chess by Program 
Power is a great improvement, mainly because 
it is now in colour. The board is very clear — 
in bright red and jireen — and the pieces are 
wx^tl-defined. h plays a vigorous attacking 
game ai level 2 and makes iis moves very 
quickly. It is prone to commit a computer *s 
version of human error — that is, losing its 
queen — but obviously plays a more thought- 
ful game ai the higher levels. 

In contrast to games of death and 
destruction, BBC. Software have produced a 
tape called Games of Strategy. If there's 
anything left of your brain after a few hours of 
(ialaxians you might like to try Galaxy, 
Ciomoku, Masterbrain or Reversi. 

In Masterbrain you have to discover a four- 
figure digit the computer is "thinking" of, and 
it has to discover yours. Reversi and Gomoku 
are both we 11* know* n territorial possession 
board games. Cialaxy is another territorial 
game, pitting you — on board the starship 
luiJcavour — ;(gatnst the invading Kryons. By 
plotting co-orditiates on the screen you can 
destroy the invaders by firing phasers and 
photon torpedoes. None of these games is 
particularly interesting graphically, but that's 
not the point. If you like board gacnes or 
logical games, you might enjoy them. 

Acornsoft's version of Galaxians is called 
Arcadians and is written by someone calling 
liimself Orlando. Perhaps he really is called 
Orlando. Pseudonymously or not, Orlando 
has written a very good program; definitely 
the best available Gala.xians-style game for the 
BHC^ A jolly little tune announces the begin- 
nitig, after which you are rapidly destroyed. 
But you soon get the hang of it, and the game 
improves as you proceed through the pages. 

Although not written by Orlando, Acorn- 
iioft's Super !nvader^ is also the best of its kind 
for the BBC. It has three levels of difilculty. 
The first two, A Mild Encounter and An 




LMVCLOrE 



«auNft 



Uncomfortable Situation, are in the 
traditional mould with the invaders 
and their missiles encroaching more 
quickly on your position. In the 
third level, rather exaggeratedly 
called A Terrifying Hxperience, the 
invaders' bombs fioai dow*n and 
home in on you. They do not often 
miss. This is an exciting and well- 
executed version of a game which 
had almost lost its interest. 

Better than both these games, 
though, is Rocket Raid, 
Acornsoft*s answer to Scramble. 
You must pilot your ship over jagged land- 
scape, bombing the fuel dumps and blasting 
the rockets. The controls are similar to the 
ones used in Defender but arc more 
conveniently positioned on the keyboard. This 
first stage is deceptively simple. 

No sooner have you successfully negotiated 
these paltry obstacles than you are confronted 
by one of the most awesome sights in home 
computer games; the cavern. Grown men have 
screamed in anguish as, time after time, their 
ships has been destroyed by the viciously 
oscillating green yo-yos called phixzers. 
Kveniually of course, you get through, only to 
be confronted by the meteorites — approach- 
ing at different altitudes, they cannot be 
destroyed but must be avoided. With vour 



>2, 




nerves shot to pieces by the ordeal of the 
Cavern you do not last long here. So you go 
back, to the beginning, to the Cavern and the 
phizzers and . . . When you have flown 
about a hundred missions you might get 
through to the skyscrapers, or the ma/.e, or 
even the fabled deserted city. Then you can 
start all over again. 

All three games have excellent graphics and 
sound quality and are probably worth the extra 
money as ihey are definitely the best on the 
market. 

I,evel 9 have produced two adventure 
games; Adventure Quest and Dungeon 
Adventure. These two progratns seem to be an 
attempt to exploit the vogue for (antasy and 
role-playing games such as Dungeons and 
Dragons. Add a touch of Tolkien and just a 
hint ofConan The Barbarian and you have the 
scenario; quaintly-yclept wi>:ards and knights 
encounter evil and violence — but no sex — in 
steaming primeval forests and war-ravaged 
wastelands. 

Beneath the odd vocabulary and exot it- 
props they are, of course, ordinary' adventure 
games. As such, they are as good as any other. 
You are an apprentice wizard who, in order to 
save Middle liarth has to seek out and destroy 
the evil Lord Agaliarept in his dark tower. 
When I was an apprentice wizard I was 
quickly eaten by ravenous wolves but the 
program kindly resurrected me and I received 
the blessing of Typo, G(xi of Adventures. It 

iconiinued on page 53} 



YOUR COMPUTER, MARCH 1 983 51 



Is your Spectrum 
holding back? 

Unlock all the secrets of your Spectrum with the 
most complete Spectrum Software Library available. 




Written by the sharpest minds in micro technology today, this comprehensive library of 
software will allow you to maximise the entire range of your Spectrum's impressive 
capabilities. If you demand the best from your Spectrum, cut out and mail the coupon 
today, because once you've unlocked all the secrets of your Spectrum - there'll be no 
holdinqyouback^^ 

i:nvl;Ul^iWfl The Complete Spectrum ROM Disassembly 

This is the book for the serious programmer who wants to get right to the heart of the 
Spectrum system; its 16K ROM control program. 

Written by Dr. Ian Logan and Dr. Frank O'Hara. each ROM routine is completely 
disassembled and its function clearly explained- Great care is also taken to ensure 
the reader understands how all the routines within the ROM interact with each other. 
The book also explains every aspect of the Spectrum's software operation in detail 
and makes all functions and entry points available for use in your own programs and 
routines. £9.95 

CSjIIIIHniSpectrum Hardware Manual 

An essential aid for every Spectrum user, giving an easy to 

follow explanation of how this sophisticated micro computer 

really works, written by Adrian Dickens. 

Backed up with a complete rundown on each component's 

function and full circuit diagrams, the book reveals many 

features of the Spectrum system not mentioned in the Sinclair 

Manual. 

The book also includes practical hardware projects and tips 

enabling you to take full advantage of the system's hardware 

potential. £5.95 



Understanding Your Spectrum 

A C0fnple:e over vjew of Spectrum 
software systems explaining both BASIC 
and mactiine language programming. 
£7.95 



Over the Spectrum 

30 excittng programs and games 
to t est yo J a nd you r Spect ru m 
plus many programming hints 
ar\d tips too £6.95 



Spectrum Mdctiine language For 
Trie Absolute Beginner 
bvefy tiling ihe lir^i l«me user needs 
toknow about Spectrum Machine 
language. £6^95 



MELBOURNE HOUSE PUBLISHERS 



Please send me your free catalogue. 
Pfeasesendme: 
Books 

SPECTRUM 

understandtng Your Spectrum 

Spectrum Machine Language 

For The ADsofute Beginner 

over The Spectrum 
: The complete Spectrum ROM 

Disassembly 
i] Spectrum Hardware Manual 

DRAGON 

Enter The Dragon 



Orders to: 131 Trafatgar Road, 
Greenwich. London SE10 



£7.95 

£6.95 
£6.95 

£9.95 
£5.95 



£5.9S 



ZX81 

Ll MachlneLanguage Made Simple 
fortheZX80&ZX81 £8.95 

: Not Only 30 Programs £4.95 

Understanding Your 
ZX81 ROM £8.95 

Complete Sinclair Basic 
Course £17.50 

Basic Course cassettes £2.50 

complete Sinclair ZX81 Rom 
Disassembly Part A&8 £9.95 

J insandOutsoftheTimex 

TSIOOO £5 95 



correspondence to Glebe Cottage, 
Station Road. Chedding ton. 
Leighton Buzzard. BEDS LU7 7NA 

VIC 20 

VIC Innovative Computing £6.95 



Trade enquiries 
welcome. 



Cassettes 

16K SPECTRUM 

Over The Spectrum No. 1 
Over The Spectrum No. 2 
Over The Spectrum No. 3 
Programs from spectrum 
Machine Language Book 



£5.95 
£595 
£5,95 

£5.95 



48K SPECTRUM 

penetrator £6.95 

The Hobbit £14.95 
STANDARD VIC 20 

VIC innovative Cassette i £5.95 

VIC innovative Cassette 2 £5.95 

VIC innovative Cassette 5 £5.95 

VIC Games Pack £5.95 

The wizard i The Princess £5.95 



All Melbourne House cassette software is unconditionally guaranteed against malfunction. 
Access orders can be telephoned through on our 24-hour ansafone (01) 858 7397. 

I enclose my cheque/money order for £ , 

Ptease debit my Access card No.. 

Signature 

Address 



All prices include VAT where applicable 
£ 



Please add 80p for post and pack £_ 
TOTAL £, 



.80 



.expiry date . 



. Name. 



.Postcode 



YC3 



MELBOURNE HOUSE PUBLISHERS 



IIWJ 

JiLii 



(continued from page 5U 
did not do me much good^ and for all I know 
the Middle Earth is stilt waiting to be saved by 
a brave and ingenious adventure game fan. 

Dungeon Adventure is related to the 
previous game; now you must find the dead 
demon lord's treasure in his black tower. Both 
these programs have a Save facility and come 
with an explanatory bt>oklet. Enclosed is a 
stamped addressed envelope which entitles 
you to one clue from Level 9. 

It was encouraging to see that software 
houses are now producing more programs of a 
practical or educational intent. Program 
Power ofler Constellation, which enables the 
user to view the stars from any point on the 
I*arth*s surface, on any date and at any time. 
You enter latitude and longitude, date and 
time and telescope elevation; and, behold, on 
the screen is displayed a map of the heavens! 

You can zoom in or out, thus allowing you 
to have a close-up of one particular constel- 
lation or a broad view of the whole area. This 
program will probably appeal mainly to 
budding astronomers as an easy method of 
finding their way about the stars before going 
on to the real thing. 

If you are more interested in money than the 
mysteries of the cosmos, then Compute-a- 
draw from Davansofi will be more to your 
taste. Its manufaciuiers claim that by using it 
carefully you can predict draws with about 
20-30 percent more success than picking them 
with a pin. They do not promise you a 
fortune; only the opjX>riunity of winning 
several smaller dividends each season. 

This program comes in two parts; the pre* 
diction program, £4.9 5, and the database, 
£1330. The latter is, obviously, essential and 
the work that has gone into it justifies the 
price. It contains the results from about 6,650 
matches over the last three seasons, up to 
January 15 of this year. If you do buy this 
program, then you will have to be prepared for 
a fair amount of work; adding information to 
the database, running the program before 
making selections, reading the copious 
explanatory notes. 

Perhaps the most ditricult commands to 
master in the BBC Micro's repertoire are the 
Sound and Envelope commands with their 18 
parameters, Davansoft's Sound Editor is 
designed to make them easier to use. Ii draws 
the graphs of the pitch and amplitude 
envelopes over the same axes; the parameters 



are printed below and can be easily entered by 
moving the cursor. Wheii you alter one of 
them the program enables you to discover the 
elTect by redrawing the envelope shape and 
producing the new sound. 

BBC Software has produced two programs 
exploiting the graphic capabilities of the BBC 
computer; Painting and Drawing, both by 
Brian Smith o*' the Royal College of Art. 
Although the controls for these two programs 
are rather complex, they both come with clear 
explanatory booklets. In Painting you have a 
good variety of colours to choose from. There 
is also a choice between brush and airbrush — 
which **paints** in a cluster of dots. Other 




options arc to vary the width of brush, use 
hatching or vaiy background colours. Draw- 
ing allows you to create circles, polygons and 
other shapes with difFerent sizes and elTects. In 
both of these programs brush or line 
movement is controlled by the cursor keys; it 
is thus rather dilTicult to draw, for instance, a 
curve. If you want to explore the BBC7s 
graphics these programs could be useful. If 
you want to learn how to draw then you 
should buy pencil and paper. 

Anyone who is interested in making the 
most of the BBC Micro's graphics might be 
better advised to take a look at Acornsofl's 
Creative Graphics. Best described as a 
compendium of graphics techniques and ideas, 
the tape contains 36 Basic programs which 
produce a variety of pictures and patterns. 
These include rotating 31) shapes, animated 
pictures and elaborate and constantly- 
changing designs. 

One of the most impressive things about this 
collection is how short the programs are. Few 
oi' them would take long to key in; yet they 
achieve the sort of effects that are only 
available wiih machine coile, if at all, on most 



Company 


Software 


Price 


Company 


Software 


Price 


BBC Software, 


Games of Strategy 


no 


Acornsoft, 


Rocket Raid 


£9.95 


BBC Publications, 


Painting 


£10 


4a Market Hill, 


Arcadians 


£9.95 


PO Box 234. 


Drawing 


£10 


Cambridge CB2 3NJ. 


Super Invaders 


£9.95 


London SE1 3TH. 








Tree of Knowledge £9.95 


Level 9 Computing, 


Adventure Quest 


£9.90 




Creative Graphics 


£9.95 


229 Hughenden 
Road, 


Dungeon Adventure 


£9,90 


Superior Software, 


Centipede 


£6.50 


High Wycombe, 
Buckinghamshife 






69 Leeds Road, 
Bramhope, 


Gafaxians 
invaders 


£6.50 
£6.50 








Leeds. 


Alien Dropout 


£6.50 


Program Power, 


Chess 


£6.95 




Space Fighter 


£6.50 


Depi YC2, 


Alien Destroyer 


£6,95 




Fruit Machine 


£6.50 


8/8a Regent Street 


, Laser 


£6.95 








Chapel Ailerton, 


Constellation 


£5.95 


Computer Concepts, 


Wordwise 


£45 


Leeds LS7 4PE. 






Dept YC4 






Davansoft, 


Compute-a-draw 


£4.95 


16 Wayside, 






1 Delapoer Drive, 


Sound Editor 


£5.95 


Chipperfield, 






Haverfordwest, 






Hertfordshire 






DyfedSA61 IHX. 






WD4 9JJ. 







other home micros. This reflects both on the 
scope of the BBC Basic and the ingenuity of 
the author, John C^ownie. 

To extract niaxinium benefit from these 
programs the aspiring computer artist should 
buy the Creative Graphics book, which is 
available separately for £7.50. 

Acornsoft's Tree of Knowledge is an 
educational game in two parts. The first. 
Fruit, is intended for children of primary 
school age. Either they ask the computer, or 
the computer asks them, questions whose aim 
is to discover the fruit thought of. The 
cotnputer might ask "is it a citrus fruit?" and 
if the children do not know what this is they 
will find out, thus placing citrus fruits on the 
Tree of Knowledge. This idea of classification 
and connection is continued in the second 
program^ Class, which is meant to increase a 
knowledge and understanding of the classifi- 
cation of living creatures. You think of an 
organism and the computer asks *'is it green 
and tnulticellular?*' From your answer to this 
and succeeding questions the computer 
consigns your organism to a kingdom, a sub- 
kingdom, and so on until it has identified it. 
When it has found your creature it gives a 
smug "Flo-ho". This program is specifically 
aimed at A-level biology students — a point 
driven home to me when I was asked if my 
organism was diploblaslic, coelomate and had 
ajiotocord. For them it will be very useful as a 
means of learning why creatures are classified 
in their particular groups. Both Fruit and 
Classj although having no sound and few 
graphics, are enjoyable and worthwhile 
educational games. 

Wordwise, a word processor on a ROM chip 
from Computer Concepts, is considerably 
more sophisticated than most of the word 
processors available on tape. 

The advantage of having software in ROM 
is that it can occupy the memory space that 
would otherwise be filled by the Basic 
interpreter and so does not take up any user 
RAM. This means that there is room for 
24,560 characters to be stored — about 4,500 
words. Wordwise, incidentally, keeps a count 
of the number of words typed in, which it 
displays in a status line at the top of the screen* 

Another bonus is that a program in ROM is 
instantly accessible. To switch from Basic to 
Wordwise you simply type in * Wordwise, and 
* Basic to switch back. 

On some word processors the screen can be 
horizontally scrolled over a much wider page 
of text. With Wordwise text must be entered 
and edited in Teletext mode. It can then be 
viewed in a formatted state at 80 characters to 
the line. 

There is an extensive range of editing 
facilities most of which are easy to use. 
Sections of text can be readily deleted, shifted 
and copied; previously*Savcd text can also be 
inseried frotn tape or disc. A search option 
allows you to replace every occurrence of 
specified string of characters by an alternative 
string. 

These are just some of the features 
Wordwise oft'ers. At the moment it is probably 
the most useful word processor on the market 
and is the only one on a chip.* It will be 
interesting to see how Acornsoft's View — 
w-hich wull also be in ROM — compares. | 



YOUR COMPUTER. MARCH 1983 53 



MOZART 
LIVES 



You CAN COMPOSE instant Mozart with a little 
known opus called the Dice Waltz. In cflTect, 
this was an automatic generator of minuets. 
This claim holds true in spiie of the fact that 
Wolfgang Amadeus never heard most of the 
theoretically possible 4.6E16 variations! It was 
constructed in this manner: Mozart assembled 
176 musical bars of two typcs^ suitable for the 
two parts into which each "minuet" would be 
divided. The two groups of 88 bars were 
arranged into tables of eight columns and 1 1 
rows, each element of a column representing a 
single, three-eight bar. 

In each column the bars were written or 
seleaed such that any bar in one column could 
be played after any bar taken from the column 
to its left> and before any bar taken from the 
column to its right. In the first tabic, a 
sequence of bars selected in order from the 
first to the eighth columns would combine to 
form a minuet beginning in the key of the 
tonic, and modulating by the last bar to the 
dominant — for example C to G. Providing 
the normal symmetry, though not that of the 
traditional AABA minuet, the second table 
contributes bars opening on the dominant and 
working their way back to the tonic. Each half 
would of course be repealed, giving a total of 
32 bars per minuet. 

As the title of Mozart's work suggests, the 
bars to be played were chosen by throw^ing a 
pair of dice. The range of numbers possible 
from a pair of dice is two to 12, and so the 
rows of the two tables were labelled 
accordingly, 16 throws in all generating the 
required bars in a hopefully random fashion. 
Loaded dice would definitely have been a dis- 
advantage in this context. 

In practice, Mozart compiled three tables. 
The first two were organised in the manner 
just described, each cell containing a number 
from one to 176, pointing to one of the bars 
written out on full double staves in the third 
table. One cannot help feeling that he 
conceived the whole thing with computers in 
mind; the manuscript table of the bars was a 
serial table, and so presumably, if a sequence 



figure 6, Sampfe stave. 

MINUCTZ 
PART 1 



J?^VJ'C/4C^Ct^f l 



i 



:^ 



tt 



^ 



^ 




was to be played through on the piano or 
clavichord with any comfort, the bars would 
have to be transcribed in full on to a separate 
sheet of manuscript. 

Our program attempts to preserve the 
flavour of the original. The user actually 
throws the dice, which tumble across the 
screen to reveal the desired numbers on their 
ten faces. And to complete the charade, 
appiopriate numbers appear on the other 
two visible faces. A count of the number 
of throws made is displayed, and on 
completing 16 throws^ a tabular record 
of the dice numbers is provided. 
Next, the manuscript of the 
music generated by the dice 
sequence may be printed on the 
screen in two sections, repre- 
senting parts one and two of the 
minuet. After each part is printed, 
like the original, in three voices 
and on two staves, the option is 
given to Save the manuscript. 
This will be as hard copy if 
a printer is connected, or on 
tape as a named Screen if not. 
Then, after prompts for 
volume and tempo, and in one 
of two keys, the music will 
be played through in three- 
part harmony, and of course, 
may be repeated if desired. 
Other refinements are included] 
such as the ability to fix the dice,' 
and so generate a predetermined 
sequence of bars. 

By now the astute reader will have 
realised the raison d'etre of the hardware? 
Valiant though it is, the Spectrum beeper 
cannot cope with more than one voice at a 
time. A General Instruments chip, the 
AY- 3-89 10 provides not only the three sound 
channels needed for our purpose, but also two 
entirely independent and bi-directional I/O 
pons, each of eight bits. Moreover, the chip is 
simplicity itself to program for most purposes, 
either in machine code or Basic, and equally 
convenient to drive in hardware terms. The 
spare appearance of the PSGIO board — 
Programmable Sound Generator and 
Input/Output — will bear the latter out. 

Having said that the Spectrum beeper is not 
man enough to handle full-blooded, three-part 
Mozart, some readers will no doubt be 
relieved to hear that the software can be 
largely proved using the beeper before any 
hardware is actually connected. In fact, the 
program will automatically detect the lack of 
the interface and default to beeper. It must be 
stressed however, that the beeper routine gives 
only a very crude foretaste of the real thing. 




The circuit of the PSGIO board is very 
straightforward, using only the AY- 3-89 10, 
two cheap 14-pin LS TTL integrated circuits, 
a common eight-pin audio amplifier chip and a 
small handful of discrete components. 

It lays out naturally on O.lin. pitch Vero 
board, with very little in the way of track- 
cutting or wiring involved » A ZX-81 type 
connector should be used, since this allows the 
simultaneous use of a ZX Printer. This 
connector has 23 pins per side, as opposed to 
the 28 boasted by the Spectrum; the shell of 
the printer extender will only admit a 23-way 



54 YOUR COMPUTER, MARCH 1983 




SPECTRUM 



connector. Taking this course also has the 
advantage thai the board might be used with a 
ZX-81. 

It is recommended that the connector be 
mounted on the board itself, and the whole 
plugged directly on to the Spectrum or primer 
connector without intervening wiring. The 
Spectrum is frustratingly sensitive to the 
loading caused by even the shortest of cables. 

All of the components used in the circuit are 
readily available from the majority of suppliers 
adveriising in the electronics monthlies. 

Communication WMth the PSG is register- 



orientated. In practice, this means thai the 
programmer first tells the chip which register 
he wishes to alter or read, and then sends or 
retrieves the relevant data lo or from the 
register specified. All functions are controlled 
internally by the PSG> and may persist thus 
while the controlling program is busy with 
other matters. To perform these functions^ the 
PSG makes use of the data programmed into 
its register array, numbered 0-15. Table 1 
summarises the signal requirements of the two 
control pins of the 8910 that arc used. 

Tabh 7. 
BDIR BCt 
Inactive 

1 Read from PSG 

1 Write to PSG 

1 1 Latch PSG Register Address 

They are met by decoding two I/O addresses 

— that is, eight-bit addresses combined with 
the CPU signal lORQ — to talk to the chip, 
namely 221 and 223. The former address plays 
a dual role: OUT 221,X will prepare the PSG 
for a data transfer involving register X. On the 
other hand, IN 221 will have as its result the 
contents of the register last pointed to by an 
OUT 221 instruction: for example, PRINT IN 
221 will print those contents. The other I/O 
address used, 223, is the output data 
destination address, if you like. OUT 223, Y 
writes the value Y into the register last 
referred to by an OUT 221 instruction. 

All of the PSG registers are eight-bit 
registers, although some of them are handled 
as pairs* Note that Bit is the least significant 
bit — LSB — while Bit 7 is the nciost 
significant — MSB. If two registers arc 
combined, the register with the higher address 

— number — constitutes the most significant 
byte, the summed value of their contents being 
the low-register value plus 256 times the high- 
register value. 

The value of each register bit, of course, can 
only be either a logic 1 or a logic 0; but, in 
their proper positions, the bits collectively 
form a binary number whose decimal 



equivalent can be calculated by adding 

together the weighted values of any bits set to 

1, thus: 

BIT BIT BtT BJT BIT BIT BIT BIT 

7 6 5 4 3 2 10 

i \ i 1 1 

= 255 



1 

128 


1 
64 


1 
32 


1 
16 


1 
8 


1 

4 


1 
2 


1 
1 


1 
128 






1 
32 


1 
16 






1 
2 


1 



= 179 



If, for instance, a register contained zero, all 
bits would be reset, that is logic zero. And, to 
set a particular bit to logic 1, simply write into 
the register the decimal value of that bit, plus 
those of any other bits required set. 
Conversely, if a register were to contain 255, 
that is, all bits set to 1, and the need were to 
reset to zero bits 0,1 and 2, it would be 
necessary to write into the register: 
{255-4-2-11 = 248 

Now to move on to the PSG registers. 
Remember first of all that the chip has three 
sound channels, referred to as A,B and C; and 
note further that the two highest registers, 14 
and 15, are used to transmit and receive data 
via the two I/O ports available. The PSG 
registers arc utilised as follows: 
Register 

I j- Set Channel A Tone Period 



2 
3 



t) 



8 
9 
10 
11 
12 
13 
14 
15 



Set Channel B Tone Period 

Set Channel C Tone Perfod 

Set random noise period on all 

channels. 

Enable nois€ and/or tone on alf 

channels. Control direction of I/O 

transfers for both ports. 

Set Channel A amplitude 

Set Channel B amplitude 

Set Channel C amplitude 



Set Envelope period and shape 
according to same pattern. 
I/O Port A data 
I/O Port B data 
Channel tones are set by writing values into 
registers 0-5, each voice using two registers, 
(continued on page 57f 



figure /. The Basic program, 

"MiNUfiTZ" 

R,K. HOPKINS & H.U-L«yeRTV 1SB3 



1 CLERR URL '£^929": LOt^D ""C 
err : GO TO VRL **3" 

a sRue "R "s^cReew* 

RETURN 

3 LET ©sURL "i": LET T^^B-B. L 
ET C=>&'fr&: LET &»€•»&. . LET E=D^B- 

LET P«E*C: LET VO»C.- LET KV-^E-^ 
Bl/F: LET R-URL "^^J?!" . LET RO<=R-l' 
C: LST LD=URL "3»1S«I". LET RD =LD 
■i-Br LET DT=URL "31^1&" : LET DX=V 
RL "3199©"; LE^f UT M/RL "321i5X"; 
LET BU=VRL "32291": LET RN wVRL *' 
32201'*: LET SORT^URL "3227©": LE 
T RNDTr^URL '32a©9* 

4. our R,f^: aUT RO,F; LET PL aU 
RL "323S©">137» lIH R^>F> ir PCE 
K '3l4.1iS< > 14.6 THEN LET KY^ByKY 

36 LET 0:^URL "2Se " : LCT L -Rt«y« 
O; RRNDOMJZE. L»0: LET KY^ByKY: B 
ORDER ft: PRPER R: XNK E+O; CLS : 

LET RU^^A: LET CO=fl: f>OKE VRL "2 
36SS'* F*F; PLOT ElF^^e: DRRU R,l 
ae. DRRU 220, R: DRRU A,>12e: DRR 
U -220, R; OUER B. PRINT RT D,E;" 
DO YOU UI3M TO : *- ; RT r,E;" 1, 6R 
MSLE UXTM THE DICE 7 Of 

,"^RT F^^E^e^'* 2. PREDICT TH^ PRL 
L OP THE DICE ? Of 

T; RT F+E ♦£,«;" 3. COMPOSE RUTOMR 
TJCRLLY?"; INPLHT " ENTER 1 , 2 OR 
3 ";R»: IF R»^*'3" THEN LET RU^B: 

GO sue 9930: GO TO 207 
38 OUER R: IF R»="2" THEN LET 
CO=B 



4.0 INUER^E R; DIM MC1&.«. FOR » 
mn TO IS; PRINT RT 21, R;"T«ROU C 
ENTER J " ; PfiU^E URL "4E4 " 

4-1 LET M^INT fRND#F» +B: RRHDOH 
I2C RMD*Be4.: LET L = INT (RHD^F> -l>8 

*42 IF CO THEN INPUT "No- ON LE 
FT DICE '?";H: IF H<B OR H>F THEN 
GO TO 42 

4.3 IP CO THEN INPUT "NO. OH RI 
GHT DICE 7*;L: IF L <B OR L >F THC 

^ 52 POKe\d,H; poke RD,L: POKE 
RNDT+0,L+H-C. LET HtO+BJ^L^M^ ,^ 
50 DRTR ^3S,l»0,l&O,ieS,170^12 
3,217, lis 

60 CLS . RerSTOrfC SSB, fOf* ^ '^^m 
TO -17 STEP -27. FOR n =fl TO C: R 
EBO X^9: GO SU© S»e«.' P^XT n, CL 
S : NEXT & 

200 PRINT RT fi,R; : RRNDOHIZE US 
R DI; PLOT E,171: DRRU ^2 ^ A DRR 
U R.-14: DfiHU -22, R: DKV^W R -1*^, , 
PRINT RT B,B; INVERSE B;0*B: INU 
ERSE R: NEXT O INPUT "'ENTER' T 

o coNTiNue ";r» 

205 FOR nsB TO "22: KANOOMIZE: US 
R 3SS2; POKE 23B92,-B; PR IMF "SB 
ooao": NEXT n 

207 GO sua URL "9000-* DIH HtXi 
IF RU THCN OO TO a-^ 

210 LET Pl=b; ^^*2*^ „^!^!ISSi*^ 4E^ 

7<yyi4>";»0: xr hm^o-y*- mem to 

^aS POKE f^N,^^^ eo suei mrl "^s 

le-T PRINT RT »^'«i''P9eT"^"'*^Ji.,g<^ 

KE RN.2094 <P1-B* ♦«; GO SUB 3S00; 

INPUT " SRUE manuscript ? CV yN> 

;R»; IP R»<>"Y" THEN GO TO 230 
232 INPLTT "TITLE ? ".R»: XT LEN 
R»>F+E THEN LET R*^R*< Z^^^iFL 
224. IP IN 2S1-0-S THEN FOR N =B 

(iisvng continued on page 57) 



YOUR COMPUTER. MARCH 1983 55 






1 






Imagine Software, Masons Buildings, Exchange Street East, Liverpool, Merseyside L2 3PN. Telephone: 051 -236 0407 



{continued from page 55) 
Of each pair> ihe higher register only uses ihe 
four lowesi bits. This means thai the highest 
combined value thai can be programmed for 
any channel is: 

255 - 256 • (8 + 4 + 2+U = 4095 
An external oscillator or clock frequency is 
applied to pin 22 of the PSG chip. As a 
preUniinary> this frequency is divided by 16 
before being directed to the three channels, 
where it is further divided down by the 
numbers stored in the relevant tone period 
register pairs, producing the output frequency 
for each channel: 

CLOCK frequency 



16 • Tone Period Value 

Amplitude Control is set by ignoring 
envelope control and writing into registers 8,9 
and 10 any value from to 15, the resulting 
volume being proportional to the number 
programmed. 

To enable the channels and the I/O 
individual bits of register 7 arc used for this 
purpose as follows: 
1-0/P Channel ON 

0-l/P 1 Channel OFF 



BIT 

7 


BH 
6 


BIT 
5 


BIT 
4 


BIT 
3 


BIT 
2 


BIT 


BIT 




I/O I/O 



B 



A 



c 

1_ 



8 



B A NOISE TONES 

Writing (255-4^2-1* -248 into register 7 
would thus switch on the tone outputs of all 
three channels, switch ofT noise on all three, 
and set both I/O ports to output mode. These 
bit switches are active when zero. 

When you have built or acquired a PSGIO 
board, try the following routine, which simply 
demonstrates how to output a tone from 
channel A, and then switch it oflT. It is as easy 
as that; and the most complicated sound 
programs are little more than collections of 
similar instructions: 



Program line 

10 OUT 221,0 

20 OUT 223,200 

30 OUT 221,8 
40OUT223J0 
50 OUT 221 .7 
60 OUT 223.254 

70 INPUT "Press 

ENTER to 

switch off",A$ 
80 OUT 223,255 



Rem 

Point to channel A register 

0. 

Set tone period to 200. 

Leave register 1 at zero 

Point to register 8. 

Set channel A volume to 10, 

Point to register 7, 

Switch on channel A only 

bit now equals 0. 



PSG still pointing to register 
7. Writing 255 to it sets bit 
tol. 

Do not bother typing in the remarks; they 
are only included to make you feel quite 
certain as to what the routine is doing. Try 
adding extra lines in between lines 10 to 50 to 
program tones or noise for channels B and C. 
Remember to set the volume for each voice 
used, and to change line 60 to switch the 
required voices on. 

First the Basic program — see figure 1, The 
only points to watch are that the length of line 
I remains unaltered; music manuscript file 
names are Poked into the Save expression in 
the following line, so that any additions to line 
1 could cause havoc. Also, be careful with the 
machine-code addresses set up at the 
beginning of the program. Save the Basic at 

(continued on page 59) 



(iisting continued from page 55) 

TO LEW R»: POKE UftU "337®^" +N * CO 
DE R»(N>j NEXT N: GO SU& C FOR 
N*«a TO F^e. POKH Uftl- "£373S'WW,C 
ODC " ": NEXT N: GO TO S30 

as© LPRINT ft*: LPRINT : COPY . 
LPRIMT 

230 LET P1=P1+B: IF Pl^C THEN G 
O TO 220 

252 INPUT "ENTER UDLUME 1 1 -&,i ", 
UO: IF VOiF THEN GO TO O-E 

253 INPUT "TEMPO fl^ej " ; U : IF 
L<B OR L>F THEN GO TO O-D 

a54^ POKE U*^L " Jif3«i>" , 11S + L*F . X 
NPUT "'ENTGR^ TO CONTINUE ";f»»: 
FOR N=URL '•314.Je'* TO MAL "31!5i7" 

STEP C: LET Lo CREEK N+O^PEEK tN 
*SJ>*KY: POKE N.L'-CINT CL/OJlOl: 

POKE H^B,1HT i\^yOy : NEXT N: GO 
5U© URL "Sasa" .' CL:? : GO TO F 
3S30 LET 2aR: POKE BU , 24.0 , DIM N 
t7) : FOR U=B TO D; RflNDOMiZE USR 

SORT; LET TS=UT, LET VS=^CODE "P 
": FOR GsB TO C; FOR L =R TO D 
aS4.0 DIM Ri7> : FOR T »C TO P + Br L 
ET N(T>=PEEK TS : LET TS^TS+S; XF 

NCT1>127 THEN LET RIT)=B: LET N 

fTi =N txy -ISS 

8546 NEXT T: GO SUB 9660 

85SO LET P = ie-»>L#&e F-OR T'O TO f=^ 

S5&0 LET U=B: XF NOT SiT> TH^H G 

O TO 0630 

SS70 LET X=P^ (T-C) *ie: LET Yl=fN 

IT> -B) ftD: IF <V=CV RND yl>l*j OR 

(U*B AND Yl>ee(> on iU=C RND VI >S 
0> THEN LET H^^-n 

©S7S IF NOT Yl OR YlnF OR Yl>72 
RND U=:B RND INT CYlyF> =YlyF THEN 

LET Z-B 
S5B5 LET Y=YS+Ylr IF SCT><>S TME 
N C^O TO &610 

S5S0 IF U=^C THEN CO TO 3630 
8600 LET Y=YS+32: IF U=iB THEN LE 
T Y=Yt3S 

3605 CIRCLE X,Y,0: GO &UB 9775: 
GO TO ae30 

8&a0 CIRCLE X,Y-8; CIRCLE X,Y,G; 
PLOT X+C»U,Y. DRRU R,11*U- GO S 
UB 6770+S<T> 

8625 IF Z THEN PLOT X-E^Y: 0RRU 
S,fk: XF U=Z THEN PLOT X-£,Y-J=: D 
RRU e,R 

3626 IF 2 RND V «0 THEN PLOT X -C , 
y*^F: DRRU F,R 

8627 IF RtT) THEN PLOT X-8,Y; OR 
RU F^R: PLOT X-8,Y*C: DRRU F,R: 
PLOT X-7,Y-C: DRRU f^,F: PLOT X-E 

^Y-C: DRRU fi sf 

3632 LET 2=R: NEXT T; NEXT L: LC 
T Y6=C. NEXT G, POKE BU,24.0+U- N 
EXT U: RETURN 

8660 DIM S(7): IF NOT NlC) THEN 
GO TO 86"/0 
3665 LET 0=R; FOR N=C TO F IF N 

CN> < >N CN<^&> THEN LET 0=B 

seee next N: if not o then let 6 

rC) 1=0 LET S«E*=C; LET SfF)«C: R 
ETURN 

S670 FOR N=C TO 7: XF NOT nini T 
H^N LET S Cn> =5: LET nsn+B: GO TO 

6710 
8690 IF ncr))7n(n-D) THEN GO SU© 
3730: GO TO 8710 
S700 LET & in) ^B 
871© NEXT n; RETURN 

3730 FOR OsB TO D .' XF NlN-0-B><> 
NiN-Oi THEN LET S (N-O) =S tN-0> +8 ; 

RE'^URN 
8732 NEXT O; LET 6 fN-E) ==S CN-C) +B 
: RETTURN 

S771 DRRU D,-E#U: DRRU -^D,e*U O 
RRU R,-E: DRRU D,-E*U: RETURN 
377S ORAM D,-E*U: R^TUfiN 
8773 DRRU 0,~EihU: CIRCLE X+E,Y,B 
t RETURN 
3774- RETURN 
377S DRRU S,C,PI,- 
TURN 

900S PLOT X,Y: 
U %,^%yCi DRRU 
Oj'E: DRRU R , -* j 
RRW OVER O; R,S ; 
S , S : DRRU R ^ S ; 
9800 POKE URL ' 

"Repeal ?"%a»; 

RETURN 

9S30 POKE URL "32S'&X*' ,S^O : FOR N 
=R TO E^B: OUT R,H: OUT RO , R . U^ 
XT N* OUT R^E4E: OLfT RO,E + UO: OU 
T R.n^O: OUT RO,E+UO; OUT R,F>E: 
OUT RO,E*UO: OUT R,F*B? OUT RO , 

9835 RRNDOMIZe VSR PL: OLH" R/F+B 
: OUT RO,-B: GO TO URL "QgvO©" 
9890 LET p=DT-ia. FOR n =R TO IS: 

LET P^P^IX: POKE RNDT+N^PCEK (R 
+PEEK (PNDT+NM NEXT N: IF RU T 
HEN RETURN 

9900 CL3 : PRINT ^T C,F+E;"DiC« 
Record": PLOT R,14S. DRRU O-B^R: 

DRRU R,-70: DRRU -O-l-B^R. DRRU R 
^70. PLOT 60,75: DRRU R , "e OVEP 

B- FOR K^R TO B: PRINT RT F+K*E 
.S;"PRR~ ';K*B;: FOR N =:B TO © P 
PINT TRB S + M*0; H rK#a + NI ; . N^j^T H 

NEXT K: OUER R: RETURN 
^916 BORDER D-l-E: RRPER t>^B : XHH 
P'^O. CL6 : LET e>99S3: LET L=14.: 

CO SUB O: LET L«N4F; GO SUB O: 
LET L=N+C*F: GO SUB O: LET L *M*F 
GC SUB ©: LET L -4-4^ . GO SUo 0*6 
LET Lv^iaS: GO SUB O+B. J^ET 'frnF 
*F PLOT C,M. ; GO SVB O + C. LET :i 
= il4r PLOT CM GO Z^VB 0*C 
531" FOR N-O-B TO *S S^TER -tfl P 
-.OT N,14-: DRRU R,60: PLOT N,^&: 
DRRu* P.-^O; NEXT N: PLOT O-E-i*; 
^-j^U R,&C LET L=0-F: CIRCLE L^S 
:t.C. CIRCLE L.iS,©; CIRCLE L , S9 , 
?* CIRCLE L*6S^©: RETURN 
^^i2 FOR H»L TO L*£:iF STEP F. PL 
^T f^,H DRRU 0-B,R: NEXT N: RETU 

99^4 PLOT ^/L; DRRU E,R,C. DRRU 
-C,32.-.l. DRRU E,R,-C DRRU -9, 
- =■ ♦r - - - 6 DRRU* F ♦F , R , 3 . 5 rPi^U - 
'— C.-E.D: CIRCLE E , L , B : RETURN 
99PS DRRU F ,R. ^C : ORRU -F , -C ♦F , - 
!.; CJRCuE CM-S,©. CIRCLE IX, ti 
B CIRCLE li.M-F,B RETLRT^ 



^S'l-'-^ LET L*iRND-»C; RRNDO^?I^I: L >0 
WOSSi W=. » O 15 POKE 7iUj:T*H,RNOh 



ORRVf -D . -3 ; 



RE 



DRRU £,S*D/E: DRR 
-S , -4 : DRRU -S^S* 
DRRU S. , -5.*D^E: D 
DRRU R , -s : DRRU 
RETURN 
* 3229 1 ",54.0: 
IF R»<>"Y- 



INPUT 
THEN 



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Uisting continued on page 5$) 



YOUR COMPUTER, MARCH 1983 57 



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58 YOUR COMPUTER. MARCH 1983 



(continued from page 571 

the beginning of a tape by typing: 

SAVE ''MiNUETZ"LINE 1 
This allows it to AuioRun on loadings Line 1 
fetching the tables and machine code from 
their final position on the tape imnnediately 
following the Basic. 

Second, the bar table, figure 2, embodies the 
main data bank of the program, holding 
Mozart's 176 bars. 18 bytes of RAM arc used 
to store the information for one bar. Since all 
of them are in three-eight time> and since the 
shortest note used was a semiquaver, the 
obvious time-slot of a sixth of a bar was chosen 
as the building block of the music* There is, in 
fact, one byte per channel per time slot. Figure 
2 reveals something of the identity of the data 
by grouping them in bar "dominoes*', with 
one time slot occupying a single domino row. 

Using ASCII characters to represent the 
bytes has allowed a very compact table with a 
meaningful appearance and easy points of 
entry. Use the routine given at the end of 
figure 2 to enter the data. It mimics the 
printed listing on the screen as the bytes — in 
the form of strings — are entered, and allows 
you 10 start at any row of dominoes. If you 
wish to save the code at some stage prior to 
having entered it completely, type: 

SAVE "MINUET2C0DE"C0DE 28930,3642 
Before entering any code at all, always type 
Clear 28929. To continue with a half-entered 
table, type Clear 28929, Load in the code from 
tape, and again use the routine at the foot of 
figure 2, returning the appropriate bar to the 
prompt. 

Third the machine-code routines and tables 
— figure 3. Having completed the bar table 
and Saved it on tape, type in the little loader at 
the end of figure 3. Type Clear 28929, and 
Load in the bar table, since the materia! in 
figure 3 will be part of the same 3,642-byte 
block of RAM. Run the figure 3 loader, and 
enter each block in turn, making sure you get 
the start address right, and of course, the 
number of bytes. The start address is the first 
address given under each block and the 
number of bytes is clearly marked. 

Follow the same procedure used for figure 2 
10 save intermediate stages. Note that the 
figure 3 loader also mimics the layout of the 
printout on the screen to make checking of 
entries easier. 

In the Basic program, lines 36-200 encom- 
pass the dice loop, generating the random 
numbers for the dice and drawing the dice 
themselves in their first two positions. But as 
you might imagine, there is a fair amount of 
work involved in drawing the dice. This could 
be handled only with the aid of machine code, 
which had the added advantage of economis- 
ing on rapidly shrinking text-space. It may be 
of interest to point out thai the final dice are 
drawn initially in "invisible" ink; this avoids 
flicker since the operation of converting the 
ink colour is a lot quicker than that of 
performing the calculations and drawing the 
dice with dots. Machine-code routines used 
are Dicemain, Drawdice and Prtdots, with 
their associated tables. Another subterfuge 
used for reasons of speed is that the monitor 
Circle routine is avoided. 

Line 9890 — this short subroutine is called 

after the dice have been thrown to convert the 

(continued on next page} 



(/is ting continued from page 57} 



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us. 

R.2^ 
F-£ 

FS, 
F2* 
F2- 

Ha- 

Ol I 

u« \ 

0*5 

F*S 

e» ) 

H» ) 
Mf ! 



H» » 
Htf . 
HI ! 

He- 

H! S 

H2. 
H£, 
K2, 
>.l£* 
Hi I 
F! » 

OO- 
M0- 

oa- 

M0- 

H-e 



CWTER THE RBOV^C TABLE U*XHCi THE 
POLUOWING ROUTINE -NOTE THAT ^i^CH 
DOMINO OF CHARACTERS REPRESENTS 
ONE BAR ^ AND THAT THE. CHARACTERS 
ARE ENTERED AS S , THREE -CHARACTER 
5TRXNGS, TAKEN FROH ROUS I TO S 
OP THE DOMINO IN TURN 
N-B. IP XNyERTED COHHAS APPEAR 
IN A STRING, SIMPLY TYPE THEM 
TWICE, & THE COMPUTER UILL AEAO 
IT AS ONE SET 



2 POKE 23&SS,1^: CLS ; INPUT 
"STARTING BAR -7 *' , SB : LET PscSSOa 

•a+SB^is 

4. FOR N=SB TO 133 STEP e: PRI 
NT INUERSE i;N;; FOR 0=6 TC S' F 
OR R-0 TO S 

6 INPUT **3*CHAR STRING ",A»: 
IF LEN A»<>3 THEN INPUT FLASH 1, 
"ERROR; PRESS ^t^fTmR ";A*. CO TO C 

© FOR K=0 TO 2; POKE P-*K4-R*3 + 

B Tie, core as i'Kti,i -33: next k. pp; 

INT AT 0+R,4*e*S;A» 

lO NEXT R; NEXT B : INPUT "NEXT 
SET OF S BARS lY^N/ ? 'MA*: IF A 
*3*'Y* THEN LET P=P-l^iOe; CLS : NE 
XT N 

12 STOP 



figure 3. 



HOTETABLE i 1©* BYTES) 



31*14 








148 


6 


4 2 


6 


314.20 


210 


s 


12S 


S 


47 


5 


31426 


229 


4 


15© 


4 


92 


4 


31432 


29 


4 


226 


3 


171 


3 


314-38 


11© 


3 


6© 


3 


21 


3 


31444 


233 


2 


191 


2 


152 


2 


314S0 


114 


2 


79 


2 


46 


S 


31456 


15 


2 


241 


1 


213 


1 


31462 


177 


1 


162 


1 


139 


1 


314€»e 


116 


1 


96 


1 


76 


4 


31474 


57 


1 


40 


1 


23 


1 


314e0 


7 


1 


249 





235 





3l4eS 


221 





209 





197 


© 


31492 


186 





176 





166 





31498 


157 





14© 





140 





315C4 


132 


o 


126 





117 


& 


31510 


111 





105 





99 


O 


31S16 


93 


e 










DICETABLCS (176 BYTES} 






31S1© 


21 


6 


62 


36 


66 


65 


31324 


39 


96 


34 


3 


12 


21 


31530 


6 


62 


16 


66 


SS 


39 


31S36 


47 


112 


75 


12 


111 


102 


31S42 


123 


91 


127 


25 


134 


82 


31S48 


38 


129 


10 


37 


56 


13 


31S54 


73 


41 


131 


49 


46 


122 


31S60 


S4 


64 


86 


lis 


119 


126 


31566 


71 


120 


61 


110 


67 


107 


31572 


26 


99 


42 


50 


2 


©0 


31S78 


61 


105 


74 


103 


43 


33 


31S84 


11 


106 


90 


124 


32 


95 


31590 


20 


133 


55 


116 


©7 


5 


31596 


29 


S 


29 


5 


29 


S 


31602 


29 


5 


29 


5 


63 


94 


31608 


S9 


7© 


23 


10© 


13 


97 


31614 


S8 


83 


31 


9© 


35 


109 


31620 


138 


113 


64 


121 


76 


69 


31626 


4 


19 


24 


101 


14 


7 


31632 


57 


118 


45 


44 


18 


2© 


31638 


88 


9 


51 


104 


30 


100 


31644 


27 


137 


130 


72 


128 


79 


31650 


45 


136 


52 


60 


68 


62 


31656 


39 


47 


34 


53 


12 


45 


31662 


17 


52 


125 


66 


G2 


132 


31668 


47 


34 


53 


12 


69 


93 


31674 


114 


48 


1 


22 


77 


65 


31680 


117 


13S 


40 


© 


B 


8 


31686 


8 


© 


8 


8 


70 


70 


31692 


70 


8 










DRAUDICEDRTfll 


fa52 BYTES* 




31694 


17 


26 


16 


31 


18 


21 


31700 


16 


31 


17 


26 


18 


21 


31706 


16 


31 


20 


27 


18 


21 


31712 


14 


25 


16 


31 


20 


27 


31718 


18 


21 


14 


25 


17 


26 


31724 


16 


31 


18 


29 


20 


27 


31730 


18 


21 


16 


23 


14 


25 


31736 


11 


29 


10 


32 


11 


26 


31742 


10 


32 


11 


29 


11 


26 


31748 


10 


32 


14 


32 


11 


26 


31754 




26 


10 


32 


14 


32 


31760 


11 


26 


7 


26 


11 


29 


31766 


10 


32 


12 


32 


14 


32 


31772 


11 


26 


9 


26 


7 


26 


31778 


12 


22 


e 


24 


16 


20 


31784 


S 


24 


16 


20 


12 


22 



16 
16 



31790 © 

31796 12 

31O02 

3180© 

31814 

31620 14 

31826 13 

31S32 13 

3133S 11 

31844 15 

31850 13 

31856 IS 

31862 

31860 

31874 

31880 

31886 

31892 

31898 

31904 

31910 

31916 

31922 

31928 

31934 

31940 



8 

7 
7 
4 
8 

7 

a 

Q 

s 

5 

9 

13 

5 

13 



24 

20 

20 

24 

20 

9 

14 

14 

a 

4 

14 

4 

12 

15 

15 

9 

9 

IS 

9 

5 

7 

7 

3 

3 

7 

3 



12 

© 

12 

10 

14 

13 

14 

17 

13 

11 

15 

13 

7 

© 

11 

7 

4 

9 

6 

5 

13 

9 

5 

9 

7 

11 



24 

24 

20 

24 

20 

14 

9 

10 

14 

© 

12 

6 

15 

9 

15 

15 

9 

15 

9 

7 

3 

7 

7 

3 

7 

3 



16 
12 

12 

12 

12 

IS 

IS 

15 

17 

14 

17 

11 

8 

© 

8 

11 

6 

11 

4 

13 

9 

13 

9 

9 

9 

9 



DRRWD1CEOATR2 C12 BYTES) 



31946 5 
31952 5 



4 
1 



6 
5 



3 

6 



6 
4 



20 

24 

22 

24 

20 

4 

4 

4 

10 
O 

10 

8 

9 

12 

9 

15 

12 

15 

9 

3 

B 

3 

7 

5 

7 

3 



5 

1 



DRAUDICEDATA3 t40 ©YTES> 



31958 47 

31964 1 

31970 65 

31076 

31982 

31988 

31994 



45 1 1 

255 4 7 47 

24 255 1 

255 65 25 

55 1 

255 45 45 

S5 1 



65 22 

255 255 

55 

1 255 

55 

1 1 



DICCHAIN (102 BYTES) 



31998 
32004 
32010 
32016 
32022 
3202© 
3S-034 

^O: r. 
^ot ;/ 

2053 
320t:4 
332*70 
32076 
32062 
32068 
32094 



253 
123 
197 

17 
229 
61 
129 

42 
205 

Ge 

33 

205 

34 

253 

88 



35 



54 

58 

229 

42 

17 

32 

125 



129 

160 

140 

100 

125 

54 

1 

32 

120 



85 

159 

245 


200 

251 

209 

225 

125 

125 

80 

125 

92 

85 

192 

2 

177 





125 

205 

241 

124 

26 

19 

25 

209 

193 

34 

33 

205 

7 

54 
32 



33 

6 

129 

225 

19 

21^^ 

26" 

229 

225 

16 

125 

4 

100 

33 

lae 

7 
243 



206 

2 

125 

25 

19 

205 

17 

213 

25 

208 

9i2 

104 

125 



254-^ 

11 

201 



ORAwL>li:i: i2^ 6VTfcS.. 

32100 217 229 217 6 1© 33 

32106 214 124 197 76 35 70 

32112 35 94 35 86 35 229 

3211© 205 186 36 &&S 193 16 

32124 239 217 225 217 201 

PRTDOTS (30 BYTES) 

32129 71 197 175 87 95 131 

32135 28 28 16 251 95 25 

32141 193 197 70 35 78 35 

32147 229 205 217 13 62 111 

32153 215 225 193 16 24© 201 



NRTTABLE (51 BYTES) 



32225 


1 


1 


2 


2 


3 


4 


32231 


4 


S 


5 


6 


6 


7 


32237 


8 


8 


9 


9 


10 


11 


32243 


11 


12 


12 


13 


13 


14 


32249 


IS 


15 


16 


16 


17 


1© 


32255 


18 


19 


19 


20 


20 


21 


32261 


22 


22 


23 


23 


24 


25 


32267 


25 


26 


26 


27 


27 


2© 


32273 


29 


29 


30 








NOTE SORT 


(74 BYTES) 






3227S 


17 


161 


125 


213 


33 


209 


32282 


125 


6 


8 


197 


70 


35 


3228© 


229 


213 


33 


240 


112 


17 


32294 


18 





25 


16 


253 


209 


32300 


6 


6 


126 


35 


35 


35 


32306 


18 


19 


16 


248 


225 


193 


32312 


16 


227 


225 


6 


4© 


197 


3231© 


126 


6 


51 


184 


40 


6 


32324 


16 


251 


175 


119 


24 


15 


32330 


17 


224 


12S 


19 


16 


253 


32336 


26 


119 


27 


26 


190 


32 


32342 


2 


203 


254 


35 


193 


16 


3234© 


224 


201 










PLAYHAIN 


(77 BYTES) 






323B0 


6 


2 


197 


197 


6 


e 


32356 


17 


209 


125 


197 


26 


19 


32362 


213 


71 


33 








17 


32368 


18 





25 


16 


253 


1 


32374 


240 


112 


167 


9 


6 


6 


32380 


197 


205 


171 


126 


6 


121 


32386 


14 


2SS 


13 


32 


253 


16 


32392 


249 


193 


16 


240 


209 


193 


32398 


16 


215 


6 


20 


14 


2SS 


32404 


13 


32 


253 


16 


249 


193 


32410 


16 


197 


33 


101 


126 


54 


32416 


217 


193 


16 


3 


54 


209 


32422 


201 


197 


4 


24 


162 





PLRYSLOT (38 BYTES) 

32427 175 245 211 221 17S 190 

32433 32 6 205 209 126 17S 

32439 24 14 70 17 182 122 

32445 19 19 16 252 26 19 

32451 205 209 126 26 205 209 

32457 126 35 241 254 6 200 

32463 24 219 



OUT (22 ©YTCS> 



32465 6 
32471 6 



16 
16 



254 211 223 
254 193 241 



(listing continued on next page) 



YOUR COMPUTER, MARCH 1983 59 



(continued from previous page} 

dice numbers into equivalent bar numbers. 

Lines 9916-9925 draw the blank 
manuscript, and lines 8530-8775 — see figure 
6 — actually print out the music. Each voice is 
printed out in full before moving on to the 
next voice* The appropriate data is fetched 
from the bar table by the machine-code 
routine Notesort, Lines 8771-8775 actually 
print the noies> U being a flag to determine the 
direction in which the tails are drawn, Z being 
another flag indicating whether leger lines are 
required. 

Line 9900 is a subroutine to prim out the 
record of dice numbers. 

Lines 9800-9835 play the music. The PSG 
is initialised in Basic before caUing the 
machine code which actually outputs the 
music. The first entry point to the subroutine 
is at line 9830, the routine re-entering itself 
from line 9800 if a repeat is desired. Which 
machine-code routines are called depends on 
whether a PvSGIO board is connected. If it is 
then Playmain is called, which in turn uses 
Playslot and Out. If no soundboard is detected 
then Musicbox is called, which simulates a 
musical box playing through the top voice 
only; even the clicks of the wards are included. 
Seriously though, the Musicbox routines — 
including Part and Beepout — are really only 
intended to verify the softw^are as a whole if 
you have not yet got hold of a PSGIO board, 
and though fun, is no substitute for the real, 
three-voice original. On the PSGIO board, an 
output socket is provided to allow you to plug 
into the Aux input of your amplifier: this 
arrangement really does justice to the music. 

Lines 207-253 call the manuscript drawing 
and play subroutines when required, and 
handle Saving of manuscript, as well as setting 
up volume and tempo variables. 

Line 253 changes key each cycle, according 
to the factor KY. 

Finally, a note on 170: the two registers, 14 
and 15 in the PSG give 16 bits of TTL- 
compatible I/O capability to the PSGIO 
circuit. As pointed out earlier, the ports can be 
driven completely independently of the sound 
generation; while sound is being output, I/O 
operations can be performed. The ports arc 
bidirectional. Bits 6 and 7 of register 7 are 
used to dictate which direction is operational 
for each port; if either is set to one then the 
corresponding port is in output mode, if a zero 
setting, then the port is in input mode. The 
possibilities are endless. 

There is nothing to stop anyone substituting 
his own bars for the Mozart using the 
information given in the text, and with the 
limitations that with the current arrangement 
only triple-time music can be accommodated. 

Those familiar with machine code should 
find it relatively easy to cope with duple times 
by changing the number of slots and the cycle 
counters which handle them. 

Some programmers will be unwilling or 
unable to deal with the effort of punching in 
the whole of Minuets, or building the 
programmable sound generator and input/ 
output board. If they wish, they may write to 
Rod Hopkins at 5 Greenside, Leslie, Fife KY6 
3DD for a copy of the program at £3.25, or the 
fully-built PSGIO board together with the 
program for £19.75. Both prices include 
postage and packing. 



(fisting continued from previous page) 


"PRTDOTS** 




3a4.77 GO 


21X aai 24-5 197 


6 


GETNUM 


LD 6, A 


3fi4.©3 1 


16 254 201 






PUSH BC 
XOR A 


MUSICBOX 


<aS BYTES) 






LD D,R 
LD E.R 
ADD A,E 


324^87 6 


2 197 62 225 


167 


QETDOTPAT 


32493 214- 


S 16 252 50 


25 




INC E 


324.^9 126 


aes 127 193 


16 




INC E 


32S0S 23Q 


62 209 50 25 


126 




DUNZ GETDOTPAT 


32511 201 








LD E,A 
ADD ML,DE 


PORT (23 BYTES) 






POP BC 








NXTDOT 


PUSH BC 


32512 33 


59 126 5* 201 


229 




LD B, CHL) 


32518 205 


20 126 205 23 


127 




INC ML 


32S24 6 


255 16 2S4 205 


23 




LD C^ (ML) 


3253d 127 


S2S 54 6 201 






INC HL 
PUSH ML 


BCCPOUT C3© BYTES* 






CALL SETPRTPOS 










LD A ^ CODE *'0" 


32535 33 


161 12S 6 46 


197 


PRTDOT 


AST 10H 


3254-1 229 


239 52 126 4 7 


e 




POP HL 


3254-7 


20 56 225 126 


2® 




POP BC 


32553 254- 


32 2 62 


69 




DUNZ NXTDOT 


32559 229 


205 40 4S 205 


24© 




RET 


32S&S 3 


225 193 16 226 


201 


-NOTESORT 


LD DE.UOICESTO 
PUSH DE 


















LD ML..RNDTABLE 


ENTER EfiCH OF THE ftBOUE DUMPS IN 




LD B^BARCOUNT 


TURN USING THE POLLOUING 


ROUT- 


NXTBAR 


PUSH BC 


INE. IN EACH CRSE THE STRRT 




LD B, (HL) 


RDDRE55 IS THE FIRST RDORCSS 




INC ML 


SHOUN FOR 


THAT DUMP 






PUSH HL 
PUSH DE 
LD HL,BARTRBLE-16 


2 INPUT -NUMBER OP BYTEe *? "; 




LD DE^BARSTEP 


B : INPLH" * 


'START RDDRESS •? 


"; S 


GETBAR 


ADD HL,DE 


4. FOR N»3 TO S + B-l STEP 6; PR 




DUNZ GETBRR 


INT N; : FOR K =0 TO 5 

6 INPUT "NEXT BYTE 7 " ; 


fl: POK 




POP DE 

LD B^SLOTCOUNT 


E N+K,R.- PRINT TAB ©+K*4;R;; IF 


NXTSLOT 


LD A, (HL) 


N4>K^54^B-a 


THEN GO TO lO 






INC ML 


© NEKT 


K PRINT : NEXT 


N 




ZNC HL 


10 STOP 








INC ML 
LD (DE) ,A 
INC DE 

DUNZ NXTSLOT 
POP HL 


Figure 4, 








POP BC 








DUNZ NXTBAR 


MI^CH INfc CODE DIS5ft5&£M©t.Y 






POP HL 

LD B.BRRS^SLQTS 


•C*JCi?MRIN 


., 




NXTSLOT 


PUSH ©C 
LD A, (ML) 


INKOPF 


LDtRTT-T) ,0 






LD B.TOPNOTE 




l_D HL^DRTRl 




NOTE? 


CP B 




L.t> R, <LHDlCENO> 






URZ NRTEOUIU 




LD B.DICE C^U/JT 






DJN2 NOTE*? 


NXTi>ICE 


PUSH BC 
PUSH ML 
PUSH RF 






LD A,B 

LD (ML) ,A 

UR PTNXTSLOT 


PRTOPFRCE 


CALL PRTOOT.S 




NATEOUXU 


LD DE,NATTRBLE-1 




1_D DE,FRCESTEP 




GETNAT 


INC DE 




POP ftp 






DUNZ CALCNAT 




POP HL 






LD A, (DE) 




ROD HL.DE 






LD tHL) ,A 




PUSH HL 






DEC DE 




LD DE,DRTR2-2 






LD A, (DE) 


URLIDNUM 


INC DE 
INC DE 






CP (HL) 

JRNZ PTNXTSLOT 




DEC A 

URNZ URLIDNUM 




PTNXTSLOT 


SET 7, (ML) 
INC HL 




LD R , <DE> 






POP BC 




PUSH DE 






DUNZ NXTSLOT 


PRTLHFRCE 


CALL PRTDOTS 






RET 




POP DE 




^•PLA-r'MAIN' 


• 




INC DE 










LD R, CDE) 

LD DE.FACESTEP 

POP HL 




REPEAT 


LD B^PRRTCOUNT 
PUSH BC 
PUSH BC 




ADD HL . DE 






LD Br.BRRCOUNT 
LD DE.RNDTABLE 




PUSH HL 








PUSH DE 




NXTBAR 


PUSH BC 


PRTRMPRCE 


CALL PRTDOTS 
POP DE 
POP ML 
ADD ML, DC 






LD A, (DE) 
INC DE 
PUSH DE 
LD B,A 




LD A, CRHDICENO 

POP BC 

DUNZ NXTDICE 




CALCBAR 


LD HL,0 
LD DE, 16 
ADD ML,D£ 


DRRUCU6E9 


LD HL.RHPLOTCORDS 




DUNZ CALCBAR 




LD tPLOTX>'} ,HL 






LD BC, BART ABLE -1© 




CALL DRRUDICE 


• 




AND A 




LD HL ^ LHPLOTCORDS 




fit>£> HL , BC 




LD (PLOTXYJ ^HL 






LD B,SLOTCOUNT 




CALL DRRUDICE 




NXTSLOT 


PUSH BC 


INKON 


LD (ATT-T) ,7 






CALL PLAYSLOT 


NXTPOSN 


LD ML, ATT -FILE 
LD BC^SCRNSIZE 
LD R. IHL) 
CP INK0 
URNZ DONE'? 
LD (HL) , INK7 




LOOPl 
LOOPS 


LD B, COUNT 1 
LD C,COUNT2 
DEC C 

URNZ LOOP2 
DUNZ LOOPl 
POP BC 


DONE'? 


DEC BC 
INC HL 
LD R,B 
OR C 






DUNZ NXTSLOT 
POP DE 
POP BC 
DUNZ NXTBAR 




URN2 NXTPOSN 
RET 




LOOPS 


LD B, COUNT 1 
LD C,COUNT2 






LOOP4 


DEC C 


•*DRRUDICE' 


• 






URNZ LOOP4 
DUNZ LOOP3 


5RUERET 


CXX 

f>VSH HL 

EXX 

LD B.SIDECOUHT 

LD HL,DATR3 






POP BC 

DUNZ REPEAT 

LD HL,RRNDTRBPOINT 

LD (HL) ,PART3POINT 

POP BC 


NXTSIDE 


PUSH BC 
LD C, (ML) 
INC ML 






DUNZ REPEATa 

LD <ML> ^PARTIPOINT 

RET 




LD B> CHL) 




REPCRT2 


PUSH BC 




INC HL 






INC 6 




LD E, tHL) 






UR REPEAT 




INC ML 










LD D, tHL) 




'PLAYSLOT' 


• 




INC ML 










PUSH ML 






XOR A 




CALL DRRU 




NXTUOICE 


PUSH AF 




POP ML 






OUT P.EGADDR,A 




POP ©C 






XOR A 




DUNZ NXTSIDE 






OP <HL) 


UN5TKRET 


EXX 

POP ML 
EXX 
RET 






URNZ GETNOTE 
CALL OUT 
XOR A 
UR MIOUT 
LD B, (ML) 



60 YOUR COMPUTER, MARCH 1983 



CftLCNOTE 



MIOUT 



"OUT" 
LOOPl 

LOOPS 



LDOP3 



l_D DE^NOTETRBLE-S 

INC DE 

INC DE 

OONZ CflUCNOTE 

L.D fi^ tDE) 

INC Q£ 

CALL OUT 

LD a, tOE) 

CALL OUT 

INC HL 

POP AF 

cp e 

JR NXTUOICE 



LD B^ COUNT 
DUNZ LOOPl 
OUT 2a3.A 
LD 8, COUNT 
DJNZ LOOPS 
POP BC 
POP RF 
INC A 

OUT aai.A 

PUSH AF 
PUSH ©C 
LD B, COUNT 
DJNZ LOOP3 
RET 



NOTE 



P5T &BH 

DEF© 

OCFB 

DEFB 

DEFB 

DEFB 

DEFB 

DEFB 

POP HL 

LD A. CHL) 

INC HL 

CP NONOTE 

URNz Norrc 

LD R^NONOTE 

PUSH HL 

CALL STKACC 

CALL ROHBEEP 

POP HL 

POP BC 

DJNZ NXTSLOT 

RET 



Figure 5. 

RAM ALLOCATIONS A^OUfT RAMTOP 



PBQ30- 
314-1^- 
31*>13- 
31694. < 

3siee* 

3ai£9 
321S9- 
3S161- 
32309- 

322TG- 
32350- 
3S24.7- 
324.65- 
32*3'7- 
32512- 
3SS35- 



314-13 
31G17 
31^93 
31997 
320^9 
3212a 

32isa 
32i&e 

32203 
32224. 
3227S 
3P34.9 
324.2e 
324.&4. 
32436 
32S11 
32534. 
32S70 



©RRTABLE 

NOTEl-flBLE 

DICLTrt©LE3 

DRRUDXCEDATA 

DICEMf^IN 

DRrt UDXCE 

PRTDOTS 

DXCENOSTO 

UOICE5TO 

RNDTAS 

NHl rRBLC 

N0TE30RT 

PLflVMAIN 

PLAY SLOT 

OUT 

HUSXCSDX 

PRRT 

BHEPOtn" 



Circuit diagram 
for (tte sound- 
generator board. 



"MU&IC BOX* 

HXTPART 

GETPART 



•PRRT' 



LOOPl 



LD B/2 

PU&M BC 

LD A ^255 

AND A 

SUB 8 

DJNZ GETPART 

LD (RNDTABLO) ,A 

CALL PART 

POP BC 

DJNZ NXTPART 

LD A^RNDTLO 

LDtRNDTRBLO) ^A 

RET 



UD HL^NOTESORTEND 

LD (HL> ,RET 

PUSH HL 

CALL NOTE SORT 

CALL BEEPOUT 

LD B, COUNT 

DJNZ LOOPl 

CALL BEEPOUT 

POP HL 

LD(HL) ^"LD>B" 

RET 



"BEEPOUT-* 



NXTSLOT 



LD HL.UOICESTO 
LD B> SLOTS 
PUSH BC 
PUSH HL 







o^ 




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YOUR COMPUTER. MARCH 1983 63 



10 REM riflGGOTS CO M* PERCY JflN-^ea 

20 CLERR 2000'X«128*Y«96'I«12e'O«96 

30 Sf1«»RNDC 4 > ' SC«0 ' riL« 1 

40 CLS'PRINTI2200."mA99otfl'* 

50 INPUT "FflST OR SLOW< F/S >" ; S* 

60 IF S»*"F" THEN POKE 8<HFFD7.0 

70 CLS^ PR I NT'* READY! !"; 

80 PLRY"V30T10O3L6CL3O2GGL2EEL1CC" • CLS 

90 REM DRRW f^CREEN 

1 00 PMODE i / 1 * SCREEN 1.0' PCLS2 -' C0L0R4 . 2 

1 1 DRAW " BM6 . 6 J C4 i R243D 1 e0L243U 1 80 '* 

120 PflINTC0.0>.4.4 

130 GOSUB 150 'GOTO 220 

140 REM PUT FOOD IN RRNDOM POSITION 

1 50 R-RND< 240 )+e ' D-RNDC 1 78 )+8 

160 FOR M«l TO RNDC4) 

170 IF PP0INT(R+M.D+M>4 THEN 150 

180 PSETCR+M.D+M.l) 

190 SOUND 100; 1 

200 NEKT M 

210 RETURN 

220 REM MOVEMENT 

230 ON SM GOTO 290.360.430.500 



Fast and tricky, M Percy's 
Maggots will soon have 
you wriggling at the 
keyboard. 

This addictive high-resolution game for the 
Dragon 32 does wonders for the reflexes and 
gets away from the era of laborious games with 
a ready-set maze. 

Due to the amazing speed with which the 
Dragon works in Basic, this game — in which 
a red maggot runs around the screen and 
searches for food — can be very hard. A speed 
option is offered: this is done by setting the 
internal timer ro a running speed of 1.8 MHz 
instead of the default of 0,9 MHz. 

The idea is to move the maggot — which 
starts off in a random direction^ but always 
from the centre position — round the screen, 
to the clumps of food which are represented by 
green dots. Movement is achieved by the use 
of the arrow keys. When a clump of food is 
eaten the maggot increases by a length or two. 

Turning should be kept to a minimum 
because the maggot sloughs its skin. If the 
maggot hits this or the border then the game is 
lost. As more and more corners are turned the 
screen fills up with red lines. The bigger the 
maggot the longer the barricade of dead skin 
will be. 

When the maggot has reached a length of 40 
the game stops for five seconds. The screen 
then clears and play starts again^ but instead of 
starting off 10 segments long> it starts with 
two so that more epithelia will be descarded, 
making the game harder than before. When 
three sets have been cleared the internal timer 
is set to Fast mode so that the game> if started 



in Slow, will now be fast. The game then 
continues with a new set appearing each time 
the maggot attains a length of 40 units. 

Due to the way the end of the maggot is 
preset to keep it at the length specified by ML 
and the variables I and O a skin or 
skin segment immediately behind the maggot 
may disappear. This will only happen when 
turning and may be used to an advantage to 
reach food which was inaccessible — but be 
carefiil that the food is not erased as well. 

Lines 20-30 clear room for the strings and 
set all necessary variables; lines 50-60 
determine speed; and lines 70-120 set display. 

In line 130, the Gosub moves to the food 
routine: the Goto is for starting the game. 

Lines 150-200 place a clump of food in a 
random position with line 170 checking to see 
if the point is already set to read, and if so 
starts the routine again. Up to four blocks of 
food may appear in one clump or as little as 
one — variable M determines this. Line 150 
places the food in the yellow area of the screen 
only. Line 230 starts the maggot moving in the 
appropriate random direction by the variable 
SM, and goes to the appropriate line number; 
lines 240-280 send control to the appropriate 
line number, and line 290 checks to see if any 
of the arrow keys have been depressed. 

If none has been depressed or if the reverse 
key has been pressed, then the maggot 
carries on moving in the same^ 
direction or else 




i 



64 YOUR COMPUTER, MARCH 1983 



back to lines 240-280 for the next direction. 

Line 300 checks to see if the next point to be 
PSei is red and if so moves the losing routine 
at 580. Line 310 checks to see if the next point 
is food and if so goes to the appropriate routine. 

Lines 330-350 subtract the length of the 
maggot from the PSet position and preset 
these points so that the maggot does not 
appear as one continuous line. 

Line 590 speeds the routine up and 700 
slows it back down. Lines 790-850 search for 
food in an area of three by three around the 
maggot's head and for each little block found 
five points are added to the score. Line 840 
then presets these points so that no food is left 
in that area. Line 860 goes lo the routine for 
placing some more food in another random 
position. Line 870 adds two to the length of 
the maggot. Line 880 checks to sec if it is 40 in 
length and if so goes to the routine at 900. 

Lines 900-950 clear the screen and add 1 to 
the amount of sets cleared. Line 940 makes the 
game fast if a fourth set is reached. Line 950 
gives the maggot a length of two and continues 
the game. Variable ML can be changed in line 
880 to make the game 
easier or harder. 



(continued from facing page) 



240 

250 
260 
270 
280 
290 

300 

310 
320 
330 
340 
390 
360 
370 
380 
390 
400 
410 
420 
430 
440 
490 
460 
470 
480 
490 
500 
510 
520 



B«-' 
780 




IF B*-CHRii<94> THEN 290 

IF B«*CHR*(10) THEN 360 

IF 0»-CHR«<B> THEN 436 

IF B«-CHR*<9) THEN 500 

GOTO 240 

B»«INKEY*'IF B*"CHR»<10> OR 

IF PP0INT<X>Y>4 THEN 580 

IF PP0INT<X.Y)-1 THEN GOSUB 

PSET^ X Y 4 ^ 

I«X'6«Y+f1L'IF 0>184 THEN 0-184 

PRESET< I . ) 

GOTO 290 

B»-INKEY»'IF B*-CHR*<94) OR B*- 

IF PP0INT<X,Y>4 THEN 580 

IF PPOINKX.YJ-l THEN GOSUB 780 

PSET<K>Y;4) 

I«><.0-Y-ML'IF 0<8 THEN 0-8 

PRESET< 1 . > 

GOTO 360 

Bf-lNKEYf -IF B*-CHR»<9) OR B*-" 

IF PP0INT<><;.Y>-4 THEN 580 

IF PP0INTCX,Y)-1 THEN GOSUB 780 

PSET<X/Y/4> 

I«X+ML'0-Y'IF I>242 THEN 1-242 

PRESETS 1 , > 

GOTO 430 

B*«INKEY*'IF B*-CHR*C8) OR B*-" 

IF PP0INTCX.Y>-4 THEN 580 

IF PP0INT<X.Y>-1 THEN GOSUB 780 

PSET<X>Y.4) 

I-X-ML'0-Y'IF I<8 THEN 1-8 

PRESETS 1 . ) 

GOTO 500 

REM PRINT SCORES 

FOR E-0 TO 250'NEXTZ 

POKE 84HFFD6>0 

FOR C-1 TO 4 

PLAY " V3 1 T200O 1 CDECDECDE " 

DRRW"C*'+STR«<C) 

DRflW"Bni20. 100J S8j R5U5L5U5R5" 

DRRW"BM137.100J88;U10R5D5L5" 

DRflW"Bni52. 100J SB; NR5U10" 

DRRW"BM166. 100;S8jU10R5D10U5L5" 

DRflW"Bni80> 100J S8j BR5U10NL5R5" 

NEXT C 

SOUND 1.20 

POKE 84HFFO6.0 

FOR Z- TO 100'NEXT2 

CLS' PR I NT "YOUR BODY WAS"; ML; "CMS LONG." 

PRINT"RND YOU SCORED" ;Sj "POINTS. " 
740 PR I NT "AND CLEARED ">SC; "SETS" 
750 INPUT "ANOTHER GO<Y/N)"iB« 
760 IF B»""N" THEN END 
770 RUN 

780 REM SEARCH FOR FOOD 
732 FOR B— 2 TO 2 
800 FOR V— 2 TO 2 

810 IF PP0INT<B+X.V+Y>1 THEN 820 ELSE 850 

820 SOUND 230.1 

S-S+5 

PRESET<B+X.V+Yj2) 

NEXT V.B 

GOSUB 150 

ML-ML+2 

IF ML-40 THEN 900 

RETURN 

FOR 2-0 TO 600 'NEXT Z 

CLS'PRINT"RNOTHER SET COMING UP" 

PLAY " V3 I I DDD02CDEFG02CDEFG " 

SC-SC+1 

IF SC-3 THEN POKE tHFFD7.0 

ML-2'GOTO 100 



THEN Y-Y-2 ELSE 240 



THEN Y-Y+2 ELSE 240 



THEN X-X-2 ELSE 240 



THEN X-X+2 ELSE 240 



YOUR COMPUTER, MARCH 1983 65 



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reprints 



If you are interested in a particular article/special 
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66 YOUR COMPUTER, MARCH 1983 



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CH AMPIONSH IP . ...SO..W... 





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/^* 




WIN A FABULOUS 'WINGS' 
HOLIDAY FOR 2 TO FLORIDA. 

VISIT THE AMAZING NEW 
EPCOT CENTRE 

Volcanic Dungeon, the addictive adventure. People have 
been known to venture into its nnaze of caverns to rescue the 
Princess Edora again and again. If you are one of them, or 
wish to be, then you could find yourself tying on a sun- 
drenched beach in Miami for a week. Foliowed by a 
further week at Orlando, visiting Disney World and 
Epcot. So what do you have to do for all this? Just be the 
best Voicanic Dungeon player in the UK, that's all! Ten 
finalists will battle it out in the championship at the London 
Computer Fair, Earl's Court, in June 1963, But first you 
must prove you are worthy. 

Volcanic Dungeon is available on the 16K ZX-8T, 48K 
Spectrum and Dragon 32. An entry form is supplied with 
every game. (Anyone who already owns the^origiinal ZX 
version can enter by sending a SAE for an entry form J 
Order y out copy NOW from CARNELL SOFTWARE. 4 
Staunton Road. Slough, Berks. Only £5.00 including 
P&P,i^lso available from good microcomputer stores. 

/'Judges' decision is final and no correspondence will be 
Jiered into. All business associates of Carnell Software, 
^^hd their relatives, are disqualified froni entry. A copy of the 
- rules of the Volcanic Dungeon championship will be 
supplied with the entry form. > 



\ 





v^ 



o 





mt 



With forth now available for home 
computers and the release of the Jupiter Ace, 
users suddenly have a machine and a language 
ideally structured to games thai are fast, 
involved and without the relative complexity 
of machine code. Forth's compact program- 
ming means one can develop and test each of 
the elements of the whole program as one 
builds it up. 

The disadvantage of not being able to code 
from the top down^ as in Basic, is overcome 
easily by either flowcharting the proposed 
program or doing a simple logical list of its 
component parts. 

The Jupiter Ace I used for this program has 
an actual memory availability for user Forth 
words of less than IK. This may seem very 
little but it gives one suflicient space to create 
versions of popular arcade games that contain 
the main features of the originals and run very 
close to their speeds. In fact, I found that 
Pac-Man written in Forth actually runs faster 
than the game played at the local amusement 
centre. As it is one of the more popular games 
and contains many of the building blocks one 
would use in other games I chose it as the 
example for this article. 

I have included all the main points of the 
arcade version, except for the power pills 
which would take up an extra 500 bytes at a 
rough estimate. 

I have assumed that you understand the 
basic words used in the Ace but include an 
explanation of the specific techniques 
involved. To conserve memory the variables 
and words used have short names but I 
comment on each separately. 

The sequence for the game is as follows. 
First, the graphics used for the man, ghosts^ 
dots and wall are defined and the screen 
created. Next the variables are initialised and 
the man and ghosts placed in their starting 
positions. 

The way the man moves is broken down 
into the following steps. First, a check to sec if 
an appropriate key has been pressed, and the 
program continues with this sequence if it has. 

The Inkey function on the Ace returns to 
the stack the ASCII value of the key pressed. 



FOxTHiACE 



This has to be converted into a number giving 
the change in position in the display file. The 
Ace display file is laid out in 24 rows of 32 
columns, each at addresses 9216 to 9984. An 
up or down movement changes the memory 
location by 32 and a left or right movement 
changes it by 1 . I have used these numbers lo 
give the new location of the man. 

Next the program checks to make sure the 
man does not bump into a wall and continues 
only if there is no risk of this. 

Then a space is put in the man*s last 
position, and the new position is checked to 
see whether or not it contains a dot. If it does, 
the score is incremented. If this score means 
that all the available dots have been eaten, the 
screen is refilled. 

Now the man is moved to his new position 
which is stored in the appropriate variable. 
The ghost-moving section comes next. I found 
that this was most easily done by having a 
separate variable for each ghost's position 
which is put into the variable used by the 
subroutine as each ghost is moved. 

The sequence for each ghost starts by 
checking whether the ghost should move up or 
down or neither according to the relative 
position of the man, and then makes sure that 
it docs not hit a wall. A random generator is 
used to allow the ghost only limited movement 
— the game would be impossible if the ghost 
was always correct, and boring if its movement 
were fully predictable. When a ghost moves, 
the space it leaves is replaced with a space or 
dot as appropriate. This is done by a method 
which is explained fully in the actual coding. 
The same procedure is used for left and right 
movement of the ghost. If the man now 
occupies the same position as one of the ghosts 
the game ends. 

Obviously all these procedures need 
additional subroutines to generate the random 




The maze display: snappers and gu/pers thrive in this son of environment 
:Z INVIS CLS 




Ralph Hilton gets his 



teeth into Forth gannes^^ 
Have an Ace munch. 



numbers and refill the screen with dots when 
required. 

The game is loaded in three sections to make 
full use of the memory but no reloading is 
necessary to replay. 

First, the graphics section is prepared, I 
have assigned user graphics for the wall and 
dots as this makes it far easier to type in the 
screen itself. The graphics arc placed into a 
section of RAM which is calculated as starting 
at 11264 plus the ASCII code of the character 
one is defining multiplied by 8. As typing in a 
list of binary digits is tedious I have converted 
all the values to decimal. 

Here is the listing for the graphics section: 

: NM 36 126 219 90 126 255 126 36 ; 
This w^ord puts the values used for the ghost 
on to the stack. It is a separate w^ord because it 
is needed several times, 
: GR8* 11263 + DUP 
8 ^ 
DO 

+ LOOP ; 

This word takes nine numbers from the stack; 
the first eight define the character and the 
ninth is the ASCII value of the character. It 
makes a loop, using as its limits the sections of 
memory at the beginning and end of the space 
we want to fill. It then puts each of the 
numbers into its appropriate place. It is taken 
from the Ace manual. 

: A851708517085170851701 GR Wall 

24 24 02 GR Dot 

28 20 8127 8 2034 653 GR Man 

NM 5 GR 

NM 35 GR ; 
When you have typed this in, A will run the 
routine and store the characters appropriately. 
This section should then be saved on tape by 
starting the tape plaver then entering 
SAVEGRAPHICS 



68 YOUR COMPUTeR, MARCH 1 983 



FO^ GAMES 




variable X 
variable W 



variable Y 
variable Z 



You can then verify it as explained in the 
manual and delete it from memory using 

FORGET NM 
to leave space for the next section, the game 
itseif. 

For this section first enter the variables; 
variable A The score. 

The man's position. 
Used for the position of the 
ghost being moved. Y and Z 
are moved to W as needed. 
The positions of the two 
ghosts. 

Only two ghosts have been used — a third 
would fit in the memory but with the speed at 
which the program runs would make it almost 
impossible to win, 

variable SD This holds the random number. 
variable K This sets the difficulty level. 
The subroutines used by the main words need 
to go in next so that the compiler recognises 
them when called from the upper words. 
: B This fills the screen with dots wherever 
there is no wall and is used whenever the 
dots are all eaten. 
3856 9216 

DO Sets a loop to go over the whole 
screen. 

i c@ 1 = = Checks that the space does 
not contain a wall. 
IF 

2 i c! Puts a dot there if it does not, 
THEN 
LOOP 
5 Y @ cl 5 Z @ cl Puts the ghosts back on 

the screen. 
Y @Z@ = IF8 Y @ c! THEN 
When a ghost leaves a position then 3 is 
subtracted from the ASCII value of the 
charaaer so that it is left as it was; dots use 2 
and spaces 32 so the ghost is given values 5 
and 35j and 3 is added to the ASCII when the 
ghost is moved there. Here if the two ghosts 



are in the same place when all the dots are 

eaten then 2 + 3 + 3 has to go in that space 

giving a dot when they both leave. 

K @ DUP 2 > IF 1- THEN K » Increases the 

difficulty level if it is not at maximum; 

: RNO This is taken from the Ace manual and 

covered there. 

SD @ 75 u* 75 D + 

OVER OVER u< - - 1- 

OUP SD! 

u' SWAP DROP ; 
:CPS 

This is used to add 3 to the position that the 
ghost moves into and add 253 when it leaves* 
Adding 253 achieves the same as taking away 3 
as one is using a single bvte. 

SWAP OVER c@ V SWAP c! ; 
Next the main routines are typed in. M is the 
routine for moving the man complete with 
associated checks and score changing. The 
comments could be typed into the machine 
but would take up valuable memory and so 

should be omitted. 
: M 
INKEY DUP DUP 
52 >SWAP 57 <AND 

This checks that the key is one of the cursor 
control keys 5 to 8; these have ASCII values 53 
through 56. 
IF 
52 - DUP Puts the number into the range 1 

to 4 
4 MOD 1 > 31 * 1 + MOD gives the 
remainder after dividing by the preceding 
number so cursor keys 6 and 7 will leave 
32 on the stack while keys 5 and 8 leave 1 
on the stack. 
SWAP 3 < -2 • 1 + • This multiplies the 32 
or 1 obtained by -1 if 
keys 5 or 6 were 
pressed. 
X @ + DUP c@ DUP Leaves on the stack 
the new value of X and two copies of 
what X currently contains. 
1=0 = 

IF Continue only if one will not collide with a 
wail. 

32 X @ c! Put a space in the old position 
of the man. 

2 = 

IF Check if the man is eating a dot. 
A @ 1 + DUP DUP A 1 21 AT . 
326 MOD 0= IF B THEN Add 1 to the 
score; print the score; check whether all 
the dots have been eaten and refill 
screen if more left. 

THEN 

3 OVER cl X I Put the man in the new 

position and store the value 
of X. 
99 40 BEEP 
ELSE 

DROP DROP Removes unused numbers 

Irom stack. 
THEN 
ELSE 

DROP 
THEN ; 

The routines G and H are used together. H is 
used twice by G to actually move the ghost, H 
should be typed in before G. 



: G W @ DUP X @ 16 <32 ' Compares 
the values of X and W to see whether or 
not the ghost should move down. It puts 
32 on the stack if it should. 
SWAP X @ 16 - > - 32 - - H puts 32 
on the stack if the ghost should move 
up, and then uses H to move it appro- 
priately. 
W @ 32 MOD X @32 MOD > - 2 * 1 -^ H 
Puts 1 or 1 on the stack after comparing 
the horizontal positions of X and W to 
move ghost left or right, 
: H W @ + DUP c@ Finds the new position 
of the ghost. 
1=0^ Makes sure that it is not in a wall. 
K @ RND 0- AND Uses the difficulty 

variable K and RND to 
limit the probability of 
the ghost's movement, 
IF 
253 W @ CPS Puts a space or dot where 

the ghost was. 
3 OVER CPS Puts the ghost on the 

screen. 
W ! Stores the new position of the ghost 
ELSE 

DROP 
THEN : 
The routines are now linked together by the 
program word which is Run. 
: RUN FAST 
9249 X ! 9339 Y ! 9479 Z I Sets initial 

positions of man and ghosts. 
A t Zeros score. 6 K ! Sets initial difficulty. 
B Fills the screen with dots. 

3 9249 c! Puts the man on the screen . B 

;B puts on the ghosts. 

BEGIN The main control loop. 

M Move man. 

2 @ W ! G W @ Z ! Moves the ghost Z by 
putting its value into W which is used by H. 
Y @ W ! G W @ Y ! Does the same for Y. 
X @ DUP Y @ = SWAP Z @ = OR 
UNTIL Compares X to Z and Y. If either 
equal X then the procedure ends 
otherwise it goes back to Begin, 
SLOW 

999 999 BEEP : 
The game is stored entering 
.SAVE RUN 
The screen is created and, then saved as a 
series of bytes. Enter 

: 2 INVIS CLS/' 
leaving enough space between the CLS and .'* 
so that there is only one space left at the end of 
the line. Use Shift 9 to put the Ace in graphics 
mode then, using A for the wall and B for the 
dots, type in the 20 lines of screen per the 
attached diagram. On the next line type " ; 

Entering Z will now give you the screen in 
the correct position and it can be saved on to 
tape by entering 

8192 768 BSAVE screen 
Start the tape and press enter. 
Clear the memory with 

FORGET 2 
The program is now loaded with 
LOAD GRAPHICS 
A 

FORGET NM 

Enter these three together and then start the 
tape. Stop the tape when you see the cursor. 

INVlS LOAD RUN BLOAD SCREEN 
Enter this and then restart the tape. Stop it 
when the screen is full. You can now play the 
game by entering Run. 

If you have queries about the program I can 
answer them. Write to me with stamped, 
addressed envelope at 23 Grimston Avenue, 
Folkestone, Kent. H 



YOUR COMPUTER, MARCH 1083 69 



If you are buying an Oric 1 computer, you 
are acquiring a piece of microelectronic equip- 
ment that is the state of the art in home 
computers. Inside the Oric case is a 6502 A 
central processor unit, CPU; two 2764 read* 
only memory — ROM — chips;a 6522 
versatile interface adaptor, VIA; and eight 
4164 dynamic random access memory — 
RAM — chips as well as a number of other 
integrated circuits. 

All these circuits are mounted on a printcd- 
circuit board and there are inputs and outputs 
to connect the computer to the outside world. 
That hardware specification produces a 
computer that will calculate using one or more 
high-level languages, control a printer or some 
other peripheral piece of equipment, interface 
with a Modem for communicating via British 
Telecom telephone lines or store and retrieve 
information from a mass-storage unit called a 
floppy disc. The Oric computer must contain 
nearly one million transistors and uses perhaps 
five watts of power. 

You may be forgiven for having a bias* 
attitude towards "the chip**. Although home 
computers continue to develop at breakneck 
pace, a number of small machines with a built- 
in Basic interpreter have been available for 
three or four years in this country. 

But compare, for a moment, the Oric with 
the Mark 1 computer built at Manchester 
University in 1948. Like the Oric the Mark 1 
used dynamic memory. Flip-flops, the elec- 
tronic circuit at the heart of static memory 



INCREDIBLE 



( 



devices, had to be constructed out of EF-50 
pentode valves and the quantities that would 
have been necessary were simply not a 
practical proposition. 

So Professor Williams, the head of the 
development team, invented a way of storing 
binary numbers using a 12in. diameter 
cathode ray tude, CRT, roughly similar to the 
tube in a portable television. He found that it 
was possible to detect the presence or absence 
of a pulse by the charge generated in a plate 
held against the front of the CRT — where the 
picture would normally be displayed. The 
charge decayed in about 0.2 seconds but if it 
was refreshed within that time, it w*as possible 
to store 2,048 bits for a period of several 
hours. 

The memory for a stored-program electronic 
computer was the most troublesome problem 
at that time. Other groups worked on the 
development of memory storage using 
mercury delay lines in which a vibration, or 
sound wave, was put into one end of a trough 
of mercury and recovered some time later at 
the other end. 

This technique was also dynamic because 



Figure 3. Memory circuits get cheaper 
100 



Solid state random- access memories 

(bubbles, semiconductors) 



10 

c 
a> 
o 

in 
o 

>% 

Q 

E 




-4 
10 H 



-5 
10 H 



-6 

10 H 



10 



Convention 
magnetic tape 



Video disc 




1960 



~n 1 — 

1970 1980 



— r 

1990 



— jCA^Jyf^ iUii 





-3 \0{{[4Xz 
1 j I o^ao 



Figure 2. The first computer program. 



trf \0\ 



the impulse had to be recirculated constantly if 
the information was not to be lost. One 
advantage of the Williams tube over the 
mercury delay line was that it allowed random 
access, while the mercury store was a serial 
device where one bit chased another dowm the 
trough. 

The Mark 1 computer had a 32-bii word 
length compared to the eight-bit bytes that are 
now standard in the Oric and other home 
computers. The main store of the machine 
consisted of a single Williams tube storing 32 
words, and — as far as one can make any 
comparison — that is matched by the 48,000 
bvtes available in the full Oric. 



70 YOUR COMPUTER, MARCH 1983 



.HRINKINQ 



Left: an Oric f 
\ dearly dispiaying 
its 6502A CPU, Far 
left: tfie first 
Mark 1 
program. 





The arithmetic logic unii^ ALU^ simply a 
part of the CPU in the Oricj consisted of a 
subtractor built from valves and an 
accumulator and was made — once again to 
save cost — out of a Williams tube. The Mark 
1 took 1.2ms. to carry out each instruction — 
about 800 instructions per second. 

Figure 1 is taken from History of Manchester 
Computers, National Computing Centre, and 
shows the instruction set for the Manchester 
Mark 1 — the world's first stored-program 
electronic computer. Figure 2j from the same 
publication, shows a revised version of the 
first computer program, the first program 
actually ran in June 1948. 

Some 18 months later an enlarged version of 
the Mark 1 was doing useful work for the 
University and IBM was negotiating for the 
use of the Williams tube under licence in its 
701 series computer. 



John Dawson fixes the micro- 
scope on the market that grows as 
its commodites get smaller and cheaper 
-thanks to less costly integrated circuits. 

COMPUTERS 



Magnetic drums were built to increase the 
quantity of information that could be stored 
during a program*s execution, and Ferranii 
marketed its Mark 1 computer, based on the 
Manchester design^ with a drum backing store 
that would hold 3,750 words. The drum store 
could be extended to hold 15,000 words. 

Remember that this was a computer that 
was sold both in this country and abroad and 
which provided a "computing powder far in 
excess of the University's own requirements". 
Hardware was an accurate term for these 
machines. The weight of the valves and other 
components meant that rigid metal frames 
were required to support the circuit boards. 

As one small part of the whole machine, a 
computer of the late sixties using a ferrite core 
store with a capacity of 4,000 bits would have 
a frame about the size of a single-bed mattress 
with driver amplifiers and read circuits to 
store and recover the state of each core in the 
small block in the centre of the chassis. 
Contrast also the 25 kilowatts consumed by 
the early Manchester computers with the 
power requirements of the Oric. 

Later, in 1959, Manchester started the 
design and construction of Atlas, which was to 
be the world's largest computer. The 
Manchester Atlas was formally brought into 
service in December 1962. The machine had a 
48-bit word, 16K of main store and 8K of 
read-only store. Interrupt handling, which you 



now take for granted, was a notable feature of 
the machine and allowed the connection of up 
to 512 peripherals. An Atlas computer was 
used at the SRC laboratory at Chilton until 
1974. 

The development of the transistor around 
1947 took some time to percolate through into 
the design and construction of computers. 
Early point-contact transistors certainly saved 
power when compared to valves, but had 
rather unstable operating characteristics. 
Nevertheless computers were the ideal market 
for transistors and for the solid-state integrated 
circuits that followed. 

The reason for the success of the transistor 
in computer circuits is that digital designs 
require large numbers of active devices in 
comparison to the analogue designs used for 
communications equipment and the entertain- 
ment market. A six-transistor radio was an 
advanced piece of equipment in the early 
sixties and if it had a radio-frequency amplifier 
employing another transistor, it was definitely 
upmarket and advertised as such. 

On the other had, a central processor unit 
such as the 8085, marketed by Intel uses about 
6,200 transistors and that takes no account of 
the memory for the computer or the other 
control circuits. 

It would be comforting to think that the 
development of microelectronics for the 

(continued on page 73) 



YOUR COMPUTER, MARCH 1 983 71 



aiG SIZE ^6V2' x 11^4" (A3) 100 pages. 
Tracing Paper to overlay and copy. 



Every High-Res. Plot Position numbered 
(45,056 Prxels), 




Every Print Position 

numbered (704 items) 



600 User definable grids per pad. 











20 


















21 











, i i 1 




T 


i IT' 


f 


J ; ' 


' 


J 1 ^ ; J , 


' \ ^ 




1 h i ■ ^ 



30 ! 3M 



INPUT Lines shown On grids. 
Set of seven pens for each computer colour* 



K will improve your ZX SPECTRUM graphics 
in ¥fays you wouMnt believe possible. 



Your new ZX Spectrum is literally packed wjlh sophisticated graphics. 
Colour, High resolution. Plot. Draw, Circle. Border. Ink. Paper Colours. 
User-defined characters to name just a few! 

That's why we have packed the new S pectrum Print *n' Plotter l otter 
with every facility to exploit your graphics to the full. 

After the first few weeks of " playing" with your computer you Will want 
to get down to senous programming and planning in which professional 
looking graphics should pla/ a mapr part. 

What better way to work \t out than with a Print n* Plotter Jotter? 

The professional pad 

Print 'n' Plotter ts not just another programming pad. 

Just look at the specifications: 

BIG SIZE l6/z"x t \V*' \ 1 00 Pages — 50 Print Grids and 50 High 
Resolution Plot Grids- 

Printed on hi gh-q ualrt y tracin g paper, enabling you to overfay the pages 
for direct co-ordination between PRINT and PLOT or to copy from 
illustrations, maps, charts, photos etc. 

PRINT Grids show all numbered co-ordinates for the 704 screen 
positions, plus INPUT lines. 

PLOT Grids show every numbered co-ordinate for the 45,056 Pfxels! 

Each pad contains 600 user-deftnabfe grids for use with the BIN n. POKE 
U5R*>"' function. 

And the whole thing is fully bound with fly leaf cover and complete with 
a set of seven colour pens ! 

The simple way to get serious 

Spectrum Graphics can become very complex, so before you start to 
program the best way ts to work it out on a Print n' Plotter and save all 
those errors! 

Take for instance the common CIRCLE. W»th a Jotter you can establish 
the exact screen location for the centre in seconds, and it will stop you 
running out of screen because of a too large radius. Working our DRAW is 
Similar: pre-determine DRAW lines and PLOT positions before you start. 
With a Jotter you can build-up graphics using every facility with a direct 
co-ord*nation between each. 

For instance, correct PLOT OVER or PRINT OVER positions will be easy 
with a Jotter, 

See the show for just 95p! 

To demonstrate the graphic possibilities with the SPECTRUM JOTTER 
we have produced a cassette-based Demonstration pro g ram for only 95 p 
(inc VAT and P&P). Why not send for a copy, or order it together with 
your JOTTER? 

Just part of a range of ZX products 

The Spectrum Jotter is. of course, an upgraded version of our popular 
ZX8! Pmt WPhu^r l oiter and fiim . For ZX8 1 owners these are available 
by direct mail or through a growing number of retailers and compshops. 

The ZX8I Jotter is a 100 page Graphics pad that exploits to the full the 
graphics facilities of that micro. ZX8 1 Film is a matt film version of the 
Jotter wnich is re-usabie and ideal for copying' graphics. 

Our manual: "2X Graphics progrGmrnrn g made eas y' ' explains everything 
you need to know about using the ZX8 1 products, and when used in 
conjunction with the Spectrum cassette will prove to be the defmitjve 
guide to the subject. 



And for ZX users (whether Spectrum or ZX8 1 ) we still market Pnnter 
Pa per at £1 less than SincJairs! 

Why not write and place your order today? Graphics can be a very 
serious subject , . . Pr.nt n' Plotter products can make it easier . . . and 
better m a hundred ways you nev^r thought possible! 



J«p■^^ ZX Printer 




An illustrated eaflet is sent with all orders. 
If you require a copy before ordering 
write enclosing a first class stamp. 

To: Print n Plotter Products (YB) 19 Borough High Street, 
London SE I P'ease forward nrse the following products; 
. . ZX SPECTRUH JOTTERS @ £9.9Seach. 

ZX8i JOTTERS @ O. SO each. 

ZXei PLOTTER FILMS @ £2.25each. 

-GRAPHICS PROGRAMMING MADE EASY'' MANUALS @ £1 .SOea 

PACKS OF ZX PRINTER PAPER (S ROLLS) @ £10,95 per pack, 

ZX SPECTRUM DEMO CASSETTES @9S peach. 

PLEASE NOTE ALL PRICES INCLUDE POST. PACKING AND VAT FOR 
U.K. DELIVERIES (Overseas should add 25% for additional Surface Mail) 

Remittanceenclosed payable to Princ'n'Plotter Products. 
Please bill my Access/Bare laycard/Vlsa/Mastercard No:- 



I 
I 

I Name: . , 
I Address 

I 



"^ss^ 



I 

IVoi: PT i»! n Piottr Qf^nm Iff tviAiM '9vff ibt covMtr ' Ifom Kit loioMAg tmHn 6ri«cftti ol W k Stiiih 
• du"^' Mic'o SmH» suetinjcn, laadofi • Dmm's B«eks«feen. UOAxi ICt • Siorges 9omt«^. Bfi%W 
I • TtiOfd t^ttt^Kt & Cem^^jtftq t4e»mw9M Ttflfifd • fe<i«n»i Com^itef Stfv«t$ Oi^wwi t**vc* 



I 



72 YOUR COMPUTER. MARCH 1983 



(continued from page 7U 
computer market came about because of the 
opportunities for enhancing the lives of 
individuals or even for commercial reasons. 
Not so — microelectronics was spawned by 
missile and satellite programs and promoted 
by military and space agencies in the United 
States. 

Integrated circuits became possible only 
after someone conceived that transistors, 
resistors, diodes> and so on, could be separated 
by insulation on the same piece of silicon 
rather than the physical separation which 
previously had been the rule. In 1964, Gordon 
Moore, the director of research at Fairchild, 
predicted that integrated circuits would 
continue to double in complexity every year. 
In 1977 some circuits that were commercially 
available contained more than 260,000 ele- 
ments and Moore*s law has continued to hold 
true. 

The cost of integrated circuits has declined 
consistently. Figure 3 illustrates the down- 
ward trend for memory circuits. Changes in 
technology have helped to keep the trend 
running according to Moore*s prediction. 
X-ray lithography is a form of contact 
lithography which allows the production of 
integrated circuits with finer **wires" — strips 
of metal that connect one circuit clement to 
another — than was possible with ultraviolet 
or visible light lithography. Gallium arsenide 
offers much higher switching speeds than 
silicon and the Josephson Junction, operating 
at temperatures close to absolute zero, may be 
the fundamental component of the future. 

We may have swapped the expensive, heavj% 



Decimal value 


An early 


Modern 


Explanation of operation 


of function bits 


notation 


mnemonic 









s, C 


JMPS 


Absolute indirect unconditional jump: set 
the control register equal to the contents of 
address S. 


1 




c + s, C 


JRPS 


Relative indirect unconditional jump: add 
the contents of address S to the control 
register. 


2 




-s,A 


LDN S 


Load negative: set the accumulator equal 
to the negated contents of address S. 


3 




a, S 


STOS 


Store: copy the contents of the accumu- 
lator to address S. 


4 or 5 




a-s, A 


SUBS 


Subtract: set the new value of the ' 
accumulator equal to the former contents 
minus the contents of address S. 


6 




Test 


CMP 


Compare against zero: the value in the 
accumulator is tested. If it is less than zero, 
one is added to the control register thus 
causing the next sequential instruction to 
be skipped. 


7 




Stop 


STP 


Stop: cease automatic mode, and await 
manual commands from the operator's 


Figure 7. 


The Manchester Mark f 


instruction set. 


keyboard. 



power<onsumingj air conditioning of the past 
for a similar refrigeration plant in the future to 
allow a few cubic inches of silicon to run at 
BIPS speeds. BIPS? — billions of instructions 
per second^ of course. A few cubic inches? 
Well, the speed of light starts to slow a 
computer down when different pans of the 
machine are some distance apart. Josephson 
Junction machines will operate most 
efTiciently if the computer can be kept within a 
total dimension of a few inches in any 
direction so that electrical impulses do not 
have to travel even a few metres from one part 
of the micro to another. 
How does all of this reflect on the little Oric 



— the state-of-the-art machine? The Oric uses 
essentially the same architecture as the first 
Manchester machine. John von Neumann set 
out the principle of a computer in which the 
instructions are combined with the data^ the 
Harvard architecture separated the two. 

The beginners' all-purpose symbolic in- 
struction code — Basic — high-level language 
supplied with the Oric is beyond the dreams of 
the first pioneers in the North of England. 
After all, it was those connected with the 
earliest computers who thought^ as they gazed 
at the machine in almost religious awe, that 
four computers would be sufficient for the 
world's computing needs. H 



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HI- RES GRAPHICS 



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<Xf s£ 3© :=& *- 






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•tvi(*«Mt/^nrtitrtiii^**tn<>i>4hHi»n6i«*Aik^ 



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ComprOCSyS limited 

I enclose £39.95. Please rush me ZX.AS2M1C * manual 



MUCH, MUCH MORE 



Repeat function on all keys. Double height & fmc pitch on printer. Cassette catalogue. 120 page 
"ASZMIC GOLD" manual vMth training exercises, divcuv^ion chapters, sample programs, 
documented monitor routines & much reference information. Communicate with Basic via cassette 
(skeleton programs with machine code in RFM) or via memory using the optional software switchable 
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♦ NAME 

♦ 

* Address 



Sole UK agents: — CAPITAL COMPLTERS r.TO. 

1 Branch Rd, Park St, Si Albatis AM 4RJ. 

Phone 0727 72917. Chcquev pavable to Comprocsvs 1 td. 



YOUR COMPUTER. MARCH 1983 73 



LOAD AND GO WITH YOUR DRAGON 



32 PROGRAMS FOR YOUR DRAGON 32 

* Games Pairs 

Pontoon 

Snakes and Ladders 
Ski Run 
Castle Walls 

* Homework helpers 

Sums Tester 
Vocabulary tester 

* Graphics section 

Full explanation of all Graphics 
commands with worked examples 

* Hints and Tips 

* How to debug programs 




Dept A FREEPOST EM463 (No stamp required) 
99 East St, Epsom, Surrey KT17 IBR. 
Telephone 03727-21215. 24hr phone service. 
Prices include postage but for air mail delivery in Europe add 90p (outside Europe add £ 1.70) per item, 

A ccess and Bar clay card accepted 



PHIPPS ASSOCIATES 




THE SPECTRUM POCKET BOOK 



160pp g^ ^ ^d\ Trevor Toms, best selling author of the ZX81 Pocket Book and the Sinclair 

■^ B^ ^1 i ^'^^rning Lab, turns his attention to the ZX Spectrum — the book you have been 
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Hints & Tips 



Programs 

• Castle walls; boiling oil and lovely slurping 
noises 

• Great Fire of London; try and change the 
course of history 

• Chase; outwit the pursuing robots and lead 
them to their doom 

• Truly amazing; generate a new maze puzzle 
every go 

• Reversi; the classic oriental strategy game 
with board screen display 

• 3D Maze; race against time and three 
dimensions to escape. 

Also Available ZX81 pocket Book 138pp £5.95 

ZX80 Pocket Book 128pp £4.95 

Atom Business 1 lOpp £7.50 



Discover new ways of using PRINT; INSTR functions, 
VAL, PRINT USING, hexadecimal conversion, upper 
case conversion, load and save arrays. BEEP with sliding 
tones, automatic scroll and how to use all the machine 
features within machine code. 

Machine Code 

All the tools you need to write machine code effectively. 
Graphics tool kit — debug monitor — symbol assembler 
(with labels, all ED commands, ORG statements, forward 
and relative jumps) — disassembler (with label assign- 
ment); now you can really dig into the Sinclair ROM! 
This section alone would be stupendous value for money! 

Cassettes Spectrum games as opposite £5.(X) 

Spectrum machine code as above £5.00 

for ZX81 Nowotnik Puzzle, Demolition &Tenpin £5.00 
3 Adventures: Greedy Gulch, 

Prices Magic Mountain, Pharaohs Tomb . £5.00 

include VAT ZX81 Pocket Book Cassette £5.00 



PHIPPS ASSOCIATES 



Depi A FREEPOST EM463 (No stamp required) 
99, East St, Epsom, Surrey KT17 IBR. 
Telephone 03727-21215. 24hr phone service, mmm 

Prices include postage but for air mail delivery in Europe add 90p (outside Europe add £2,20) per item. "^^ 

Access and Barclaycard accepted 



74 YOUR COMPUTER. MARCH 1983 



Trevor Hill 
sets out a more 
comprehensive 
and user-friendly 
machine-code 
monitor for the 
Sinclair ZX-81. 

Mamy machine-code routines suffer, in my 
opinion, from some deficiency, lypically not 
disassembling all Z-80 instructions; not 
dealing correctly with RST 08 and RST 28 
instructions; not easily allowing the loading of 
other programs while the routines are in 
memory; not providing facilities for expan- 
sion; not being particularly user-friendly. 

These routines have been written in an 
attempt to overcome these difficuliies. The 
first three routines and operating system 
occupy just under 2K of memory and present 
a formidable task to input and get working in 
one go. I would therefore suggest that the 
program is broken down into several stages. 

The machine-code utility program is 
intended to provide routines that arc 
particularly user-friendly. The routines are 
tucked away in memory so that their presence 
is not noticed until they are actually required. 

Figure 1 details the Basic program which is 
loaded into the computer in the normal 
manner. Once loaded the program runs auto- 
matically placing the machine-code routines — 
initially held in a string in the variables area — 
at the top end of RAM* A reduced value for 
RAMtop is then automatically set and the 
program commits hari-kari by executing New. 
This brings into operation the revised value of 
RAMtop so protecting the machine code, and 
wipes out the loading program, giving what 
appears to be a completely empty RAM. 

Any other program on which you may want 
to use the routines can then be loaded in the 
normal way. To access the routines the 
following lines of Basic are added to the 
program: 9996 STOP 

9997 POKE 16417, 

9998 RAND USER 32598 
9^9 GOTO 9996 

The menu is displayed by Run 9999. You will 
see from figure 2 that the menu has been 
designed to accommodate up to 16 routines. 
The program now waits for you to select a 
particular routine by input of the appropriate 
hexadecimal digit. The digit is displayed and 
once checked the routine may be executed by 
Newline. 

This first routine is a disassembler routine 
which deals correctly with all the Z-80 instruc- 
tions as used on the ZX-81. In particular it 
recognises that the instruction RST 08 is 
required to be followed by one data byte and 
that RST 28 may be followed by any number 
of data bytes terminated by 34. When 
executed you are asked for the start address^ 
finish address and dump details, one to printer 
— any other hexadecimal digit to screen. 

Figure 3 illustrates the format used when- 
ever input is required: a prompt message 
followed by a question mark. 

The routines have been designed to protect 
the user as far as possible. For example if the 
routine is requesting an address it will only 




EDITOR 



accept hex digits and these have to be of 
exactly the right length. 

Once you have input the data, the question 
mark will remain until you confirm it is 
correct by typing Newline. Should you make a 
typing error this may be corrected, as in Basic, 
by using the Rubout key — Shift 0. 

In this, and any of the other routines, when- 
ever input is being requested the routine may 
be terminated by using the Break key. 

The bottom section, figure 5, is a typical 
output from the disassembler. The first 
column gives the start address of the instruc- 
tions, the second the instruction code and 
third the mnemonic. 

Since this is a one-pass disassembler, labels 
arc not included, therefore all jump-relative 
instructions give, as part of the mnemonic, the 
absolute jump address. 

If the output is to the screen then Screen Fill 
will generate the usual message — report code 
5. Display may be continued, as in Basic, by 
use of Cont. 

The features detailed for the previous 
rouiinc apply to the Print Data routine. The 
output is now data rather than instructions. 
, This Write routine enables code or data to 
be Input. The start address is requested and 
then code or data may be input. It is intended 
that each line of input should correspond to 
one instruction so the maximum number of 
bytes that will be accepted is 4. The program 
knows that each byte occupies two hex digits, 
so it will not allow an odd number of digits to 
be input. 



Figure 4 lists a suitable Hex loader* Run 100 
to list code, Run 300 to write code, and Run 
500 to execute code. 

As it stands the code in the line I Rem state* 
mcnt — figure 5 — will wipe out the Loader 
program so the following modification is 
necessary during development. 

Change byte 40A7 to C9. This is the Ret 
instruction code and will stop the routine 
executing New. Now while you arc developing 
the program you will have to manually set the 
reduced value for RAMtop each time the 
computer is switched on and before loading 
the partially completed program. This can be 
done by direct commands: 

POKE 16389. 116 
NEW, 

The menu operating system, first three 
routines and data occupy just under 2K of 
memory and the string variable has been set to 
make the top 3K of RAM available. Therefore 
IK is spare for further routines, but the 
program may be easily modified to make more 
memory available if necessary. 

The machine-code listings have been taken 
directly from the program using the dis- 
assembler and therefore should contain no 
errors but be careful not to confuse 8,B 6,5 
and so on. 

If you do not relish writing such a large 
machine-code program then I can supply a 
tape and full loading instructions for £3. 
They may be obtained from Trevor Hill, 1 
Highcroft Close, Yardley Gobion, Northants. 
ifor iistings, see page 77) 



Figure f, 

"IHREH 4.© CHPRiftCTEftS TO 
REPLRCED BY M/C 

30 RfiHO USP 16S1 + 

30 SPUE "ROLrriNeS" 

4.0 RANO U3R 16501 



Be 



Figure 2. 



HCNU 










PRINT CODE 






1 


PRINT DRTR 






S 


URXTE 






3 


INSERT 






4- 


DfcUETE 






S 


TRRN^-FER 






e 


St^i^aCH 






7 


REPt^^CC 






e 

9 


RUN CODE 












Bk 








O 








& 








e 








r 




ROUT INC -? 




Figure 3. 










e PRINT CODE 




3TRRT RODRE55 4^002 


FINISH 


ADDRESS 4.0A9 




1 FOR PRINTER 7 


Figure 4, 






^MISTOP 


' 




1130 


PRINT 


"LIST PROM" 


110 


cosue 


©10C 


\ 


1£« 


UET R = 


= X 




130 


COSUB 


6000 




14.0 


PRINT 


x«; •' 


** ; 


150 


FOR U 


r.X TO 


4. 


ie0 


LET X: 


• PEEK 


A 


170 


GOSUB 


d050 




130 


PRINT 


x»; " 




190 


UET R. 


=R-H 




£00 


NEXT O 




^10 


PRINT 






aao 


GOTO 130 




300 


PRINT 


■WRITE T0" 


310 


aosu© 


3100 





320 LET R-X 

330 SCROLL 

340 LET X=R 

3S0 OOSUB ©000 

36© PRINT X», " "; 

370 INPUT Ri 

3©0 IP R$ = '*S'* THEN STOP 

390 IP LEN R*<>a#INT (LEN R^./^^ 

THEN GOTO 370 

400 PRINT A* 

4-10 LET X»«ft*( TO a> 

4.20 OOSUB 31:^0 

4-30 POKE R,X 

4.40 LET RcR-l-i 

4-50 LEX RS»R«(3 TO I 

4.S0 IF R*>-*" THEN GOTO 4 lO 

4.70 GOTO 330 

S00 PRINT "RUN PROH** 

SIO GOSU© 9100 

S20 CL3 

S30 RRND USR X 

S4.0 STOP 

ai000 LET X = INT (R.^26©) 

^50 10 LET Y=.X 

e0S0 GOSUB S090 

©030 LET X«R-Y»a5© 

©04.0 GOTO ©0©0 

©050 Lirr x»^**" 

3060 LET K^INT (X/16) 

©070 LET X1-X*+CHR« (K+aS) 

©080 LET X*=5X* + CMR» (X-K#16+3©.* 

©090 RETURN 

©100 INPUT K% 

©110 IP LEN X«<>4 THEN GOTO dieO 

©120 LET X-0 

3130 FOR X^X TO LEN X» 

©14.0 LET X«X»16*CODE X*tll-29 

aiS0 NEXT I 



81S0 RETURN 






Figure 5. 








vosa 


2R1040 


LD 


HL. (4010) 


;-0©S 


110e00 


LD 


OE , 000© 


400© 


19 


ADD 


HL.DE 


40©9 


ES 


EX 


DE.HL 


40©R 


210074 


LD 


HL , 7400 


4.0©D 


01E00B 


LD 


BC.0BE0 


■1090 


Eoe& 


LDIft 




-^092 


C9 


RET 




4^093 


2R104.0 


LD 


HL. t401O> 


4.096 


110600 


LD 


OB , 0006 


4099 


19 


ADD 


HL , DE 


4.09R 


11O074 


LD 


DE>7-V00 


i09D 


01E00& 


LD 


©C,0BE0 


4.0R0 


EDS0 


LDIR 




40R2 


3E74 


LD 


R,74. 


40R4. 


320S4.0 


LD 


f 4^005 > *R 


40f*7 


CDC303 


CRLL 


03C3 



YOUR COMPUTER, MARCH 1983 75 




How BASICARE build into a 
completv computing package, 

PCRICON- 

plugs into 

DROMfocVQ' 

Centrotifci 
OROM— Prtntercfc. 

plugs tnCo16K 

voUttfle 

progmtm/ 




If >ou're enihusrastic about microcomputfng, sooner or laterycxi'lf ask 
yourself the question . . . "where do I go from here'^' 

This is particularly toie ifyou own a 
micro with limited expansion and 
hardware peripheral options . . . like 
theZXSK 

Nowyour question can 
be answered in three 
short words. 
BASICAf?E MICRO 
SYSTBVIS 

BASICARE are the 
inventors, devetopers arid 
manufacturers of a totally 

unique microcomputing 
upgrade system. 

It's the sort of system 
others ha^ dreamed 
about ,. a series of 
separate modules that 
perform a whole range of mK:rocomputir>g furKtions 
that s*mpiy [and firmly) stack together 

If you're confused . . , don't be . . . you only hs^ to think of it in terms of 
the way Hi-B equipment has esADlved. 

y>u buy ihe hardware you want snd add to the systemf Each module 
may ha^je a separate furxiion or integrate ftjrxtions. /And when you want 
more . you add morel 

In shoftyoucandevelopa whole rarjge of hardware options that fit 
together to form a complete package . . , "Computing" in the real sense 
ofthewordi 
And w^at a packagel 

Afjsa from It's good looks arxJ stability urxJerworlcing conditions, 
EASICARE MfCRO SYSTEMS offers a fantastic range of micro options fof 
ZXBl users. 

Of course, such a system needs a starting point from 
which to e>pand. The heart of BASiCARE'S system is a 
unique computer rnterface which we call PERSONAu 
This one unit srmpfy plugs into your ZX81 without 
modification and acts as the "brains" of the whole 
operation. 

Thereafter you choose howyou want to exparxJ 
your micro by s*mply plugging-in more rrxxJules. 



Look at the choice you have; 

PERSONA - An tntcrfacc moduie to c^ vible an ORGANIC 

MfCRO to grow orurie 2X8K 

MINIMAP - A merrx>yrnappirig device to exterid the address space of the 

ZX8\ from64KiDytesto IMt::^es, 

RAM 08 A towcost kxvpo\A^nr)efTTOfye)<parxJable fi^ 

RAM 16 I6K Add on memoiy at remarkably lowcosL 

RAM 64 - A TOJE 64K Add on mefnory 

OROM — Ultra k)w power fTx?rTK>*y backed ty rechargeable battery fornon- 

vdaDte storage of prograrm arxJ data. 

TOOLKIT— A moduie ftjiy socketed to take up to8K tytes of utilities m 

EPROM/fiOM. 

PERfCON a — A general purpose, user progfammatrfe device provtding 24 Imes 

OfifpU/OUtpUL 

FERfCON b — 24 lines of heavy duty output to access and control the outside 

world. "AxspacelTllmKiMlto 

PERfCON c — A mcxJule to dnve 90 columo printer with describe basicahe 

Centronics t^pe paraifel rnterface . „,?'^^*: "TZ 

USERPOIWoption-UserdefinaWechafaaefsavailab^^ ''"l^^emlS 

for RAM 08, DROM and TCXXXIT. brochure .. . 

Ofcourse, there's lots nx)feBASfCARE Modules (encio..^"s^r:^^;ie^T 
uTKterdevelopment irKludingjoysticks, EPRCM 
Programmer, Floppy Dsc Controller ard much more 

BASfCARE IS Che sort of system that GROWS 
when you grow . . . arxl remembei; when you 
change your micro, you will be able to change to 
a PEfSONAunlttosuityourr>ewequipmenLi 

In short, BASICARE will seiveyou 
forever . . . no matter 
how big you ^ant to growl 



I si; 










Njmc- 



Ai}dxt'%\^ 



PERSO:\# £30.25 



t)RO\tr2Kl 

rex X KIT 



#€39.S0 
i@^ €22.20 




BASICARE 
MICRO 
SYSTEM J 



SAM8(/K4l«*^£24.5ft ffRJCONA ^'£27.90 
aAMJ6 ^£2&.75 rTfaCONB ^£33.75 
k^M(A «»' £76.25 naCQNC #£41.75 

Options: USERFONT * £8.00, 

>^(t1?KinfRAfc«va £t.SO, . ^ * C7.S0 

All prices Include VAT, poit-iqt* .%nti p.ic:l<tng *n the 

ULK. {^Wrxe^vs allow 'Tt rtM%t )S « for turf. iccrrwiltj., 

•*, .: liX^fjlc: B'\' '. ." \' 



I 



_l 



76 YOUR COMPUTER, MARCH 1983 



{continued from page 75) 
Machine-code listing. 

C00 fl7fiQR9ftR DEPB 

RDeiceRe deps 

R&CiR6H» DEFB 

4-39113^4-5 DEFB 

9iE7E7C.O OEPB 

C5CiC£62 DEFB 

PB4.5ftB4.7 O^FB 

Oe4.'5kC'S4-7 DEFB 

Re>4.^pe£^ DEFB 

eeRe2e-3S DEFB 

B133£eftB DEFS 

£B£BRe^C DEFB 

«I>'9E'5kFH0 DEFS 

RiR2R335 DEFS 

3R3BHDS6 DEFB 

3iSi372R DEFS 

S94.BBD2F Z^E.f=S- 

B5CI>S3R« DEFS 

SaRS^333R OEFS 

R733C32B DEFS 

33i=<^^0'34- DEFB 

B734-B75B £>^?'& 

eS3534.B5 DEFS 

373BS92F DEFS 

S530D3E2 DEFS 

CBCB£9RE DEFB 

£PPEESE3 DEFB 

6B1RRB*F D^rB 

EBICBCI'X DEFS 

Dft4-SDft3d DEFB 

Bi5104-l^l DEFB 

^O^PiOf^Cr^ DEFB 

BC!iCFBS5B«? DEFB 

BS!ka033SF DEFS 

BF33RBRB DEFB 

35S4.35RR DEFS 

B5SS4-7RB t>^f=B 

4-9R3C7C.'3 DEFB 

3B3iRB3S O^FB 

37R6E4.33 DEFB 

C7272EB3 DEFS 

372RB33B DEFB 

2RB9ia>£B DEFB 

S1332RRC DEFB 

B3RE3SC3 D^rB 

5BR3£EB£ DEFB 

9CR4.9D9E DEFS 

CDCDCDCD DEFB 

4.9R94.7R9 DEFB 

2ESR37'9R D^FB 

GFCFBOBO DEFB 

SEiRDEES DEFB 

E.^^i^^^^^ OEiFB 

EORBRBRE DEFB 

B7B03«2kRE DEFS 

R9£EB7£9 DEFB 

e7GDeBB5 O&FB 

E2D334-S9 DEFS 

3334.B5CB D^FB 

SQ-2F-3-3BF DEFB 

DiDiDiDi DEFB 

D 1 2D£B 3 1 DEFS 

BS4.52BR7 DEFB 

l©iDR9£7 DEFB 

9FneCSB3 DEFB 

RE8B9DB6 DEFB 

csaoBiae defb 

BDaEBEl© DEFB 

4-1911041 DEFB 

15a«2731 DEFB 

CDD3D3DF DErB 

3CESEBEE DEFB 

91S1396D DEFB 

6RF97B3R DEFB 

TQQCRITS DEFB 

R4.RRflDFC DEFB 

e39eBeBB def& 

C1C7S71B DEFB 

S1R1E4.7F DEFB 

QFQ^S^CSlT DEFB 

RS29RR37 DEFB 

B137B72R DEFB 

BD31R92& DEFB 

9R2FB734 DEFB 



7C04 
7C«S 
7CieC 
7Ci0 
7Ci4. 
7CiB 
7CiC 
7C20 
7024- 
7C2B 
7C2C 
7030 
7C34- 
7C3B 
7C'3C 
7C.4.0 
7C4.4. 
7C4.B 
7C4-C 
7CS0 
7C54. 
7CBB 
7C5C 
7CB0 
7C64. 
7C63 
7C6C 
7C70 
7C74. 
7C7S 
7C7C 

7C.B« 
7CB4. 
7CBB 
7CBC 

7C94. 
7C9B 
7C9C 
7CR« 
7CR4. 
7CRS 
7CRG 
7CB© 
7CB4. 
7CB3 
7CSC 
7CC0 
7CC* 
7CCB 
7CCC 
7CDei 
7CD4- 
7CDB 
7GDC 
7CE0 
7GE41 
7GE3 
7GEG 
7CF0 
7CF4- 
7GF3 
7GFC 
7D00 
7DQa 
■7DQS 

7Dac 

7D1© 
7D14. 
7D1S 
7D1C 
7Da© 
7D2<1 
7D2S 
7D2C 
:?D3© 
7D34. 
7D3S 
7D3C 
7DAO 
7D4.4. 
7D4.S 
7D4.C 
7D50 







?l8i 


i|S8**^ 


LD HL,497tt 


7ADD PI 


POP AP 




■7Sa3 CDF07e 


CAt-U 7eFD . 




7d3e COO«79 


CAuU 7909 


LD (HL> ,eS 


7AOC F5 


PKJ^H AP 




:*9&d :.90S 


OR 7C3J 


79B© 




XHC HL 


?AOP C077 


eiT B.A 




•'^sc iei:> 


UP & . i 3 


?fB7 
7009 


3e7A 


LD (ML) »7A 


7RCX ^80D 


OR z , "^f^re 




'CaD c&s:^7» 


CRUU 7^53 


DC© 4 


fegLL %^it 


7AC3 2A3C7D 


LD HL, <7D3E) 




~630 C&»17B 


CAi_L 7aax 


7906 


CD9C79 


7Aee 0855 


BIT 2,L 




7«33 3©0S 


OR MC,793R 


79a K 


7© 


fc£ ^x° 


?Aea 3©tffo 


LD CHLI ,0© 
INC ML 




7e3» RF 


XOR R 


79ep 


PC34 


CP 34 


7AeA 23 




7536 32ai£.0 


UD t^eax) .A 


79C1 


C3 


ner z 

CALL 79©3 


7AC6 a©P9 


OR 2 , 7 AC 8 




7a3« C9 


RttT 


79C2 


CD3379 


7flED ife3ff7D 


LD f7D3E> .ML 




7a3R ai?04ie 


LD HL,A07a 


79CS 


laF7 


Ufi 79De 


7AF0 e6ae 


AND 36 




7a3D 3-&3a 


LO (KL) .3«^ 


79C7 


CD7a7A 


CALL 7A7a 


7APS OF 


RRCA 




i 7*3F 33 


INC HL 


79CA 


AF 


XOR A 


7ftF3 OF 


RRCA 




7nAO 3&70 


1.D tKU) r7a 


79CB 


CB7a 


orr 7,D 


7AP4 COOP 


RRC A 




7aaS COSE7R 


CALL 7R&E 


79CD 


aeox 


OR Z . 79D© 


7AP© ;Ja0C 


OA 2 . 76©4 




7S4.5 C07a7« 


CALL 7R7a 


79CF 


»p 


CPL 


7Ar3 210476 


LD ML , 7C04 




TCA« 7© 


LE> R.a 

C^ 7© 


7900 


4© 


LD C,6 


7AP0 KS 


%%r s-- 




7aA9 FC7e 


790X 


*7 


LD © , A 


7Arc 5c 




71^40 aoeft 


or% HZ , 7dS5 


?lil 


aAPOTP 


te^ HL,C7pro> 


7AWt> ao7D 


LD H , 7D 




r«AD aiF»7C 


L& ML.7Cr3 


SS 


ADD ML , 6C 


7f^rr Br 


»-£ *-'*?^. . 




7e«&0 CDAATO 


CALL 7BAa. 


^^90 a 


ee 


EX DE , HL 


7D00 DC 


LD L , {ML> 




7^53 lODa 


UR 7daB 


7907 


ai©07D 


LD HL-7D0e 
LD n,± 


7601 aD7A 
7603 e9 


»-R *?i7? 




70SS FECa 


CP CB 


:^90A 


7B 


OP fHL) 




T^aa-? aa33 


^A X.760B 


>9DO 


CDa97A 


CALL 7Ae9 


7604. PI 


POP AP 




1 raa9 rmmt> 


CP tD 


^fOE 


i?e 


DEC ML 


7609 CD7P 


BIT 7.A 
RCT HZ 




\ 7asB aaaa 


OR Z.?a99 


y^'OP 


7A 


fe^LL ?Alo 


7O07 CO 




7650 PEOO 


CP OD 


^©c© 


OD697A 


7806 13 


INC OE 




1 T«aF aa4>4. 


OR Z , 7aA» 


79E3 


a3 


XMC HI, 
RE6 7,fHLI 


7609 19C9 
7606 CB 


OR 7AD4 




7a© 1 FEFO 


CP FO 


79E4 


CODE 


AU3H 6C 




7a03 2a4A 


OR Z . 7BR9 


79E© 


2D 


DEC ML^^ 


LD A,L 




raSS CD4F7A 


CALL 7R4F 


^«e7 


ISIB 


5^5 •ISg* 


7600 aEEO 


LD L,CO 




^^aas 2LE.ZA 


LO L.a^. 


79t9 


CD 7*7 A 


CALL 7A7a 


7DOP 99 


SUD -L 




7a«fl FCOO 


CP 00 


^9CQ 


^^.- 


OEC ML 


701© ©r 


^^^^ * ^ 




?aac aaix 


OR Z , 7B7r 


•'9eD 


1©16 


OR 7A04 


761X 47 
.'Si a 7E 


LD ©,A 




7aaE SESC 


Lo L.ac 


:S?S 


^tr^ 


CALL 7A07 


LD A , IHL) 
CALL 7660 




7B70 FC©1 


CP 01 


OR 7Ae4 


7013 CD0C76 




7«7» «a9C 


OR ^,7a»a 


.«9PA 


C07SVA 


CALL 7A7a 


701© 23 


INC HL 




7874. aC 


INC L 




fie 


DEC HL 


7B17 DO 


i^^O A, «ML) 
SU8 ic 




7e7« FEtta 


CP ea 


PS^S 


iSS2,^ 


5^6. Z^Z^ 


7B18 DDIC 




7S77 aSQO 


OR Z , 7S32 


CD077A 


CALL 7A©7 


781 A xa 


LD CDE> ,A 




7a 79 3Eee 


L0 a'sE 


79PO 


96 


Sg^u ?}5«* 


^exa 13 


IMC DC 




7a7D 3aAa7o 


LD C704a> ,R 


>9rE 


CO A* 76 


76 xc aa 

7DXD X0P3 


INC^ ML 




Ta7C ac 


INC L 


7«fill 


^1©D7C 


LD ML,7COD 
OP 7BA* 


DON2 70 xa 




7a7F 7D 


LD A.L 


.•A04 


c:iA47e 


7©1P CX 


POP BC 




7aa«» ai 


ADD A r C 


'A©7 


axo©7D 


LD ML,7DO0 
CALL 7A76 


?B20 C9 


RET 




7aai SF 


LD L*A 


*A»A 


CD767A 

CD727A 


^sqi cts 
^622 ODOa 


pySM OC ^ 




7e»a aa70 


LD M,7D 


^A©D 


CALL 7A72 


LD 6 , ©a 




7ea4. ae 


LO L . CHL» 




CBBE 


RE» 7, <HL> 


?824. S0 


OCC HL 




7sas ee 


EX DC . HL 


;g|| 96 




7638 4C 


LD C,IHL> 




7aea Qi>x><^yn 


CRLU 7«&A 




C9 


J8g? ?? 


DtfC ML 




reti^ xoAo 


Oft 7aaB 


''A 14 


PC 


PUSH AP 
RUSH D£ 
LD OE 13PJ 


SSk"- l*s"" 




7aaa cd727a 


CALL 7A7B 


•AXS 


DS 


?8Sg §1'^''' 




7SaE COAF7A 


CALL 7A4.P 


Axe 


ixe4i© 


ADD A.C 




ra^x ca3a 


ADD R . 3© 


'A19 


CD387© 


CALL 783© 


5U0 IC 




7a»3 XBEC 


OR 7Bat 


AXC 


7D 


LD A L 


7B-2C IS 


*5E^ iE*^* '^ 




70^5 CD7a7A 


CALL 7A7a 


*AXD 


B6 


CP e 


7B2P 13 


INC DC 




7aQS CD4.F7A 


CALL 7AAF 


'AXC 


aa9a 


«JA Z . 7A2» 


7630 lOFfi 


esJEi^ -Z®^* 




7e«B aeia 


LD L . X© 


•'Aaa 


CDRD7P 


CRLL 7FAO 


7632 Cl_^ 


POP ec 




•f9k^X> FCOi 


CP ax 


"Aaa 


1BP7 


OR 7A IC 


Jggg g?'* 


^e* ^a"^* 




7eSF 300E 


^H Z,7©7P 


'^Aa9 


Dl 


POP OE 


R3T lO 




TaRx arae 


LD L , 2© 


''ASS 


CDai7B 


CALL 7©ai 


783© D7 


A3T iO 




78A3 XSDR 

7aA« 3fteB 
7SR7 xaes 
70A9 3iiao 


OR 7B7P 
LD A , OB 
OR 7BAB 
LD A . OD 


-Ra9 

-^ASA 

7AaD 

7Aai£ 


a©E7 

C9 


POP AP 

om^ A 

OR NZ,7«2 4 
RET 


7037 C9 
?S3C 2^71 


RCT 

LD DC , XOCP 

eg"-*- 5?^? 




7a AB 334. X70 


LD (70aXI^A 


gJSg'" 


LD HL , 7D4a 


76*© ©A 


f-& f*'i®*^* 




7a Av 3Eia 


LD n,xa 


7A3X 
"*a33 


LD IML > , SC 


764.1 6P 


LD L .R^ 




78aa 3a407o 


LD t7D4©l *R 
LD Ml, I7FF©J 


aa 


DEC HL 


7642 C09P70 
7d40 03 


CALL 7e9F 




7aB3 aAFa7F 


7A34 


3©©9 


LD <ML» .©9 


INC OC _^^ 




■yaea as 


INC ML 


"'AS© 


a© 


DEC HL 


764© ©A 
784.7 DP 


LD A, <BC» 




-'an? 7c 


LD A, tHLJ 


7A37 
-'A39 
■^A3A 
7A3B 
7A30 


36BF 


LD (HLl »©P 


UD LiA 




^BBB axxe7o 


LD ML.7D1B 


3C 

2B 

1 1F97F 


DEC HL 


7©*a 03 




7ailB COB«7R 
7aBE 23 
7S6P CftBC 


CALL 7Ae9 
INC HL 
RES 7, *ML* 


tr 2sv^.?s 


764.9 CDA4 70 
7iS*C C0537r> 
7e4P CDA57P 


CALL 7eA4 




7aCX CD7a7R 


CALL 7R7a 


aiFC7C 


LD ML 7CPC 


?65a C9 


RCT 




7ac4 7e 


LD A . B 

CP 6b 


7A43 

'7R44 


CD7P7A 


LD A, CDE) 


"EB3 CS 


PU!IM BC 




7BCS FECe 


CALL 7A7F 


;*6S4 OS 


PU3M DC 




Tac7 aoo« 
7ac« c07a^R 


OR MZ * 7BCE 
CALL 7A7a 


7AA7 
*^A4B 


IB 

XR 


DEC DE 

LD A. <DC> 

CALL 7A7P 


'^OSa FDCD^X4a 


PUSH ML 

OXT 6, cxvtaxi 




7©CC XBBD 


OR 76BB 


•*AA9 

7RAC 
->A4D 

7A4e 


CD7F7A 


7©BA aBOS 


OR Z.7Ba* 
LD BC, (4©39» 

CALL 04©6 




7aCE COAF7R 


CALL 7R<r 


AF 


XOR A 


78aC E04B39A© 




-?eD3 2BQ3 


CP A3 
OR Z>7B©B 
PUSH RF 


D7 
C9 


AST 10 
RET 


788© 4R 
?B«1 CDBOfiQ 




-^^DT5 F» 


^R4F 

7ABe 

7ng3 
7ft a 3 


7B 

EB97 
4F 
7© 


LD A.D 
AND ©7 
LD C,« 

LD A, a 


7684 XXE07F 


LD DC,7PP0 




78^9 aoos 


PU5H BC 

OP NZ . 7ae« 


7667 CD4e3e7D 
7686 ©SO© 
7C80 79 


LD BC,C703EJ 
LD B,0© 
LO A,C 




7aDO see© 

7aDO BB 
7BDE aOB3 
78Ea C07a7R 


LD A,(l© 

CP B 

OR NZ,78e3 

CRLL 7A7a 


PS 
©F 


PU5H ftp 
AND 38 
RRCA 
RftCA 


7B8e DBEO 

ra7© *F 

707X CDBBOB 
7874 PDCBaX<4ii; 


sua ^eg 

LD C.A 
CALL 0888 

BIT i,trv*aii 




TBES Cl 


POP &C 


7AS9 


Sp 


RRCA 


7©7a 3603 


OR Z r 7B70 




-»BCA FX 


POP AP 


7 AS A 


47 


LD B^A 
POP AP 


7»7R 3i:7© 


LD A,7© 




7eE5 X8B1 


OR 7e©B 


7ABB 


P X 


7B7C D7 


H5T 1© 




7aFP 0X93-70 


LP IIC,7B93 

LD A.*a 

LD Dt , 7FP& 


7ABC 


eacQ 


AND CO 


7B7D ex 


POP HL 




79®B 3E0a 


7^^^ 


©7 


RLCA 


■»67C D 1 


POP OB 




■r^QOa xxFa7P 


7A«»' 


CHW:? 


ALC A 


7aVP CX 


POP DC 




1 ^^O^ CDXA7fl 


CALL 7A1* 


'>AG1 


r.« 


RCT 


7880 C9 


RCT 




7^9© C9 


RET 


?Aa^ 


CDRX79 


CALL 79A1 


7681 :2HPA7P 


LD ML,C7PPn» 




750r ae 


LD DE.XOCl 


-fRas 


C3aB7B 


OP 762© 


76©* CDSBF67F 


LD DE, t7FP0l 




CALL 7D3B 


TABB 


©E©4 


LD C.«4 


7688 A7 


RND A 




OCC ML 


7RaR 


CD A 173 


CALL 79 AX 


76B9 CD8a 


aac HL,De 




79 xo 7e 


LD A,<MLI 


7ABD 


CDBE79 


CALL 79BE 


7CI6B C9 


PCT 




79X1 £&X£X«0 


SET 1, tlN'^Qll 
CP ID 
CALL HZ. ©ASA 


7R7e 


X©P3 


OR 7Aaa 


7B8C DaiC 


2H5« ^^ 




791R FEXD 
7|XC CJ^ROA 


7A7a 

''ATS 
7A79 
7A7A 
7A7B 


airE7c 

e056F67F 
eDS3F©7P 


LD ML,7CPE 
LD on, 17FP8* 
LD A, tDCl 

LD (7PP6> ,&e 




RLCA 
RLCA 
RLCA 
RLCA 
RET 




7-^23 CDF07a 


CALL 7BFD 


7A7P 


CDh097A 


CALL 7AB9 


>093 Doeoeoes 

7897 PaFODSDC 


^^El 




7993 CD0979 


CALL 7909 


7Ada 


07 


k^r 10 




7Baa 2XF97C 


LD ML . 7er9 


7AB3 


33 


INC ML 


7090 30e30OC3 


ocro 




7*a9 C09F7B 


CALL 7©9P 


7A64 


7E 


LD A, <ML> 


-rBQr 3CCO 


LD n,C0 




7QaC ai7B40 


LD ML.ACk7B 


7Aas 


COBP 


RE© 7. A 
R3T x6 


78nX 323e7D 


LD f703CI tm 




Zt^K 2&^=* 


LD IMLI -33 


?A©7 


D7 


7BA4 ftp 


XOR A 




793X 33 


XNC HL 




C9 


RCT 


7eA8 CB 


PUSH 8C 




' T-^Sa 3©79 


LD rMLl ,79 


7 A ©9 


47 


LD 6^A 


76R6 DO 


PU3H DC 




^93* COaX7B 


CALL 7eax 


7A6A 


e©©F 


AND ©r 


7BA7 A7 


AND A 




7937 FO 


ACT M 


7A3C 


CDIC 


ADD A . IC 


7eA8 aooo 


OR Z , 7665 




793a CD307R 


CALL 7R3D 


7«ac 


CDPP 


5CT 7 , A 


7BRA C67E 


BXT 7. (HLl 




7936 OCOA^ 


LD C . 04 


7A90 


77 


LD <HL) .A 
DEC ML 


76 AC aeo3 


OR HT t 7601 




^^930 CD7a7R 


CALL 7fi72 


7A9X 


a© 


TBAE a3 


INC HL 




I^-^AC 3D 


DEC C 


/A9a 


7C* 


LD A ,6 

AND r® 


78AF IBFO 


on 7BAR 




T'iAx aaeo 


JR Z.794E 


7A^3 


E6F© 


76© X 3D 


DEC A 




"54 3 CPeXTB 


CALL 7661 


7A9S 


xr 


RAA 


7©8a a3 


INC HL 




79*a 30FB 


OR HC,703D 


7A9© 


IP 


RRA 


7BB3 18Pa 


OR 78A7 




X548 xax3 


LD 0.13 


7A97 


IP 


RRA 


7888 CD067e 


CRLL 7888 




''94R C0337D 


CRLL 7a»3 


7A9S 


IP 


RRA 


-f8D6 D 1 


POP DC 




r«4D C9 


ACT 


7A99 


CBIC 


ADD A , IC 


78B9 C 1 


POP BC 




~9^C CD4 079 


CALL 7949 


7AOB 


7 7 


LO iHUt ^A 


-r6BA C9 


RET 




"--^x aaex 


OP 793* 


/AdC 


C9 


RCT 


7B©a EDa83E7D 


LD OB, I7D3E1 




^V?3 3C$X 
'^53 CX9370 


LD A,OX 
LD eC,7B93 


7A9D 


CP4© 


6rT 0,6 


7BBP 7C 


LD A, fHL> 

elT 7,R 

OR N2-78C9 




7A9F 


aox9 


OR H2-7ABA 
CALL 7Ab3 
INg DC 


7DC0 CB7P 




'i>»3 CDOa79 


CALL 79<»a 


7AA1 


CDB37A 


7aca a9©a 




^5tS C02A0A 


CALL eASA 


^AA4 


X3 


78CA CDCD7a 


CALL 7BCB^ 




'dse cD^coc 


CALL ScSc 


7AA3 


C.9 


RCT 


7ac7 irtpa 


OR 7B6B 




"-»61 C0307R 


CALL 7A3& 


7AR© 


3EOX 


kO A,©1 


7BC9 C8BF 


RCa 7^A 
CP 4© 
OR NC,7BD7 




.je4 ixcaic 
'*e7 coA97r 


feScL ?^A^^" 


7AA6 
7AAa 


ISII 


5r^ Ni?7ACA 


7aCB FE4© 
73CD 3000 




'#ort ce4.t5 


BIT 0,L 


7AAC 


X605 


OR 7A63 


78CP la 


LO (DEI ,A 




•*I^C ^3*35 


7flAC 


CS40 


BIT o,e 


/8D6 13 


INC OB 




"^6t CDrt0 7F 


7AB© 


&0^f 


OR Z,7AC1 
INC OE 


7B01 EDB33E7D 


LD I7D3CI ,DC 




-'971 xeF7 


OR 79DA 


7Ae^ 


13 


7B08 23 


INC HL 




1 '9 73 C0SBFa7F 


Ut> DC , t 7PFS > 


7ADJ 


AP 


XOR A 


78D8 C9 


RCT 




'977 COO©7t> 


CALL 7000 




l«i4 


*IR 7ACA 


7»D7 a3 


INC ML 




^si? ig?r^^^ 


LD I7FP©> ,DC 
LD A, 76 


?HI §SSf 


BIT 0,6 
OR Zj.7ACi 

INC t>i 


70D6 eD«33e7D 


LD C7D3CI ,De 
PUSH HL 




^'980 07 
;'931 X3D0 
^Pa3 00 

^9BA OEO« 


R5T i6 
OR 795E 

OA NZ , 79AA 
LD C,©4. 

si- Hii, 


^ggg 


13 


VBDD PE43 


CP 43 




7© 


LD A,» 


7Bor 3©oa 


OR NC,7BE7 
LO H^-^D 




."A9C 


ced7 


Res e.A 


7BE1 287D 




:*AeC 
7A6P 


OP 

iao9 


RRCA 

OR 7ACR 


7at3 fv^ 
-^BC* SE 


LD L^A 
LO L, (MLI 




7RC1 


CD»&7A 


CALL 7 ADD 


-^BttS Xei* 


OR 7CPD 




7AC* 
7AC8 


13 
C9 


TNC OE 
RCT 


78^7 PeS4 

7afio 30OS 


CP 84 

OA MC , 78P© 




^AC*V 


76 


LD A. 6 


70l^e 36 VD 


LD M^7D 






LD A/O 

LD ML.407B 

LD <HL) ,ea 

XNC ML 


.''AC 7 


16© X 


JR 7ACA 


70CD ©P 


LD L.A 




7990 rf!dx 
79lSa a&xA 

7g94 aX7ft4.0 

7ft57 36ea 


7mCC 


79 
13 

Ss 


LO A,C 

Inc 0± 
LO H.O 
LD L,C 


7BEE IBOB 
•»6F© aXPE7B 
7BP3 E8 
■^BF* a670 


OR 7BF8 
LD HL , 7BPC 
puan ML 
LO M , 7D 




^999 23 


"•ACO 


6li 


LD L. «ML> 


7BPB ©P 


LD L,R 




799A 3*7R 
'990 XA13 


LD (HL) ,7A 


7flCC 


26 7C 


^Stu ^&li 


7BF7 BE 


LD L, iHl^X 




LD 0,X3 


7 ADO 


CDAS7& 


7BF6 a©79 


LO M , 79 




:'9**e CDB37B 


CALL 7653 


7A03 


C9 


RET 


7BPA K9 


OP 1 HL » 




'9R1 air97C 


LD ML*7Cr9 


7AD4 
7ADS 


lA 




7BPB CDBB78 


CALL 7C08 




79A4 CP9F70 
79 A 7 C&507A 
7|aA CD7l$7R 


CALL 7B9P 


k^^^ 9i*^C^> 


7aPK ei 


POP HL 




r» 


PUSH AP 
AND 07 


7epp C9 


RCT 




RCT 


7RDa 


axD07A 


LD HL/7ADD 
JP 7Apo 








ggr n|° 


7ADO 


161E 


(ftsting continued on next pageh 





















7D54. 
7D5S 
7D5C 
7D6Q 
7D54. 



3RB928R6 
2eR91RCl 
3SBS2SRB 
1RE32EB3 
E9EFF4-FR 



DEFB 
DEFB 
DEFB 
DEFB 
DEFB 



7D5S SFC7FR17 DEFB 
7DSC G©EQi713 Z>^F^ 
7D70 7R4.530SR DEFB 
7D74 C50QF559 DEFB 

(continued on next page) 



YOUR COMPUTER, MARCH 1983 77 



(continued from previous page) 



yoTs 


SElSTTTfl 


T-DTC 


4.500S2C5 


~DS0 


9E5Sa-513 


TDSa. 


XSftFtCSSR 


T-DSS 


13T24.5QB 


■7D6C 


0TBSC50-7 


7DSe 


0BTFEoo2 


7D34. 


STCB&HSC 


TDSS 


SF90BSSB 


TDSC 


TFO-BTESl 


7DR0 


©QFR3ES6 


TDRA 


TRa-3S63a 


•T'CsRS 


CSSRFFSF 


■^QflC 


BRTRoBSB 


■7DB0 


SaCSGRTF 


~DB4. 


4-STES2SE 


"7DBS 


CF920S7R 


"7DBC 


R12FSRC5 


7DC0 


007RR4.2F 


7DCd. 


oRCSQOTR 


:=-j>cs 


RTSFSRC5 


■7DCC 


©©TRSSQ© 


7000 


S2C5RRS2 


"DDd. 


S2RRBRCS 


~DDS 


QGBQB2X5 


■7C>DC 


R2C513SR 


'?'C'E0 


4.B11.139R 


'T'OEa 


C5 13 1100 


T-DES 


BRSEBBFR 


-DEC 


BSESTFBC 


TDFO 


CASTDBBS 


'?t>1=4- 


EIDTBCES 


7DFS 


DTFR130O 


T-DFC 


DS3T13SR 


•7E\Zi0 


©^(3i0l3000 


7E04- 


•32Sfi:33BH 


7E03 


000O0C0O 


?Ee»c 


14.14-14-94. 


7ei>0« 


iCCkiS-3537 


7Ei4. 


SE333900 


7^2:18 


2e.34.S9RA 


7E1C 


iD003537 


7220 


SE3 339C>0 


7E24- 


29i2639HO 


7E2Q 


iE003C37 


7E-2C 


2E39«ftiF 


ys^is 


00SE333e 


7E34. 


2H37e9fiGk 


7E-36 


€?i?a9£fl31 


7S3C 


•SH3SRfi'^l 


7E4.0 


0^393726 


7E4.4. 


333SaB2R 


■7E43 


B722003at 


7E4.C 


2)326.3723 


7E50 


«D230ei37 


7eS4- 


2R353i26 


7£S3 


23«ft24-«3<» 


7ESC 


373R3300 


7e'5'3 


2334-29RR 


7E64. 


25302SS0 


7Eest 


273^2330 


7E5C 


29302H80 


7E7<3 


2B80303CI 


TED© 


3iaE3aaE 


TED*!- 


BSSTSO-SR 


7EDS 


391D332R 


"7EDC 


S03S39ae 


TEE© 


3"?39S02e 


T-EEJ. 


292Q3T2R 


TEES 


35386026 


TEEC 


2E33aE3S 


■7EF0 


aOS01D00 


TEF4. 


aB34.3TS0 


■7EF3 


353T2E33 


7EFC 


392R3'?S0 


TFGQ 


23TBa©79 


"7F0.J. 


SSTSaSTB 


TF0S 


237Sa37S 


-7?^i3C 


asTsasTS 


7F10 


23TS237S 


TFIA 


asTsasTS 


TFIS 


237623"?© 


TFIC 


237Sa37S 



DEFB 
DEFB 
DEFB 
DEFB 
DEFB 
DEFB 
DEFB 
DEFB 
DEFB 
DEFB 
DEFB 
DEFB 
DEFB 
DEFB 
DEFB 
DEFB 
DEFB 
DEFB 

DEFB 

DEFB 

DEFB 

DEFB 

DEFB 

DEFB 

DEFB 

DEFB 

DEFB 

DEFB 

DEFB 

DEFB 

DEFB 

DEFB 

DEFB 

DgFB 

D^FB 

DEFB 

DEFB 
DEFB 
DEFB 
DEFB 
DEFB 
DEFB 
DEFB 
DEFB 
DEFB 
DEFB 
DEFB 
DEFB 

DEFB 
DEFB 
DEFB 
DEFB 

DEFB 
DEFB 
DEFB 
DEFB 
DEFB 

DEFB 

DEFB 
DEFB 
DEFB 
DEFB 
DEFB 
DEFB 
DEFB 
DEFB 
DEFB 
DEFB 
DEFB 
DEFB 
DEFB 
DEFB 
DEFB 
DEFB 
DEFB 
DEFB 
DEFB 
DEFB 



f/isting continued from previous pagef ;p|g 




PP 


HL>4eai 


^FOO 

TF«0 
TFRQ 


iOXA 

COS37B 

3e7& 


LO 

CAl.L 

LO 


O.IA 
1« 










7F9« 


CB7K 


orr 


7, IML> 


7FRa 


OT 


AST 


■?caQ 


&s 


*»gsM 


D£ 


7FSO 


aeod. 


vIR 


S,7F01 


7FA3 


D7 


R*T 


la 


z^^h 


£5 


PU»N 


OC 


7F50 


aR7BA.a 


LO 


ML* (*ft7|» 


7FR* 


ca 


RCT 




^Ffia 


cs 


PUSH 


HL 


:»F60 


C9 


jp 


(HL) 


7FR5 


3C01 


LD 


R,Ol 


7ra3 


ana SAO 


l_D 


ML . l^0SZi 


7F«1 


aa.oo7e 


LD 


ML . 7irO(» 


7Ffl7 


32:>iAO 


LD 


cAoai) .A 




e« 


PU^H 


HL 


7F64 


0ei4 


LP 


0,1A 


•^FRR 


aiC07F 


LD 


ML , 7Fe» 




cDABaeAQ 


LD 


ec» CA02SJ 


7F56 


3eo3 


LO 


R*03 


^FAD 


300F 


LD 


IMl.1 .OF 


TF2B 


ei 


POP 


ML 


7FOa 


^93X4.9 


LD 


oc.xori 

709F 


•'FAF 


C0C07F 


CALL 


7FCe 


?rac 


£5 


PUSH 


BC 


T^FftB 


IICXIO 


I.O 


7FBa 


coao7F 


CALU 


•?rs0 


T'FaD 


«7 


aNO 


P 


TFftC 


CDQF70 


CftLL 


7FBB 


FE7» 


CP 


7ft 


^'Fac 


CD4a 


SDC 


HL,eC 


7F71 


CDS37e 


CAUL 


7Dn3 


7FO'7 


aaie 


OR 


NS , 7FCQ 


-F30 


aOFS 


OR 


2 ^ 7FS? 


7F7* 


xeF« 


DsJNZ 


7FBF 


7Fe« 


3ec« 


LO 


A. CO 


-r3 2 


v^ 


UC 


ft^C 


7F76 


B1.997B 


LO 


BC,7B99 
7B3e 


7FOB 


BD 


CP 


L 


■'Fas 


f^C 


INC 


*% 


7F7« 


C03B7Q 


CRLU 


fFBC 


Sl&W*. 


OA 


z,7Foa 


7r^* 


Jiori 


Uf3 


Z^7Fa7 


7F7C 


as 


DEC 


ML 


7FBC 


3Be9 


LD 


CMLl ,00 


:»r 3G 


ei 


POP 


MU 


7F70 


7C 


LO 


P^ (HLI 


7FC© 


as 


INC 


ML 


7^37 


C&SD07 


CALL 


fflTCD 


^F7C 


DGIC 


SUB 


IC 


7FC1 


Sa3K7D 


LD 


C7D3ei ,H|. 


■*ir3« 


7C 


LO 


P, IHLI 


7Fao 


A7 


LO 


B,** 


7FC4 


CD5370 


CALL 


7003 


7F30 


CI 


POP 


HI, 


TFSl 


07 


RUCA 




7FC7 


SB 


DEC 


ML 


7r3C 


CI 


POP 


BC . 


^Foa 


&F 


WO 


L,R 


7FCO 


C« 


RET 




TFSD 


Dl 


POP 


DE 


7Fa3 


ae?F 


LO 


H , 7F 


■^FCO 


FC77 


CP 


77 


Trae 


FC7a 


CP 


76 


7FBB 


7C 


LO 


ft, tHLJ 


7FCB 


aooo 


OR 


NZ.7FOB 
A,£o 


7F*« 


CO 


Rfrr 


Z 


7FBe 


33 


IHC 


ML 


7FCO 


3ee« 


LO 


TPAl 


FC7r 


CP 


77 


7F07 


OB 


Lt> 


H, <Mt.* 


7FCF 


BO 


CP 


L 


7F*3 


fico 


«CT 


Z 


7FaB 


BF 


LO 


L,R 


TFOO 


aBDB 


OR 


Z.7FRO 


7FAA 


CP 


ec 


7F89 


E5 


PU5M 


MC 


7FOa 


CDSC7F 


CALL 


7FBE 


7F4.S 


2oes 


UP 


MZ,VF4.D 


7Fan 


CB 


pusn 


BC 


7FOI5 


ao 


oec 


ML 


:*r4a 


C[?2A0« 


CALL 


eRSR 


7Foe 


coaROR 


CRLU 


•flan 


7F0B 


leos 


OR 


7FAO 


?«»*e 


CF 


R5T 


oe 


7F«e 


ca 


POP 


BC 


7FOa 


77 


L> 


IHLJ *A 


7r*c 


oc 


DEFB 




:^FeF 


3eee 


LD 


?^o5c> .A 


7FO^ 


70 


L> 


A,e 


^rAO 


FEIC 


CP 


IC 


vriit 


3a3C7C> 


LO 


^FOR 


BO 


c » 


L 


7r4F 


3eCF 


OR 


C . 7Fa© 


**F04 


7S 


LD 
LD 
CR1_L 


A ,B 


TFOB 


aBO« 


OR 


Z , 7FAO 


7FS1 
7Fg3 


;sig 


sg 


MC?7FaO 


*F9S 
*^F«0 


21107C 
COR57S 


ML,7£10 
7BAS 


TFDO 
-^FOC 


fSco 


INC 

OR 


ML 
7FAC' 



Tadie /. Memory map showing 


main routines only. 


Address 


Mnemonic 


Comments 


07BD 


Decode 


Finds keyboard character code: ROM. 


0A2A 


CIS 


Clears screen; ROM. 


0B6B 


PrJnt Str$ 


Prims mnemonic strina: ROM 


OCOE 


Scrolf 


Moves display up on line; ROM. 


4021 


FlagY 


Bit Ochange print position; Bit 1 -Print Newline Bit 2-dump 
to printer; Bit /change restart address. 


407B 


Restart 


Contains restart address following full screen and cont 
command. 


7400 




Spare 


7822 




bytes 


7823 


RoutineO 


Disassembler 


78E7 




Spare 


78FC 




bvtes 


78FD 


Start/finish 
addresses 


Print request for input and then call input address 
routine. 


7902 


A addresses 


Print request for the number of addresses specified by 
repisier A then call input address. 


7909 


Check Drinter 


Sets Bit 1 of FLAGS - 4001 - rf printer reauired. 


7920 


Routine 1 


Prints data. 


7953 


Routine 2 


Write. 


7983 


DEFB 


Drints data associated with RST 08 and RSt 28 instnjctions. 


79C7 


Data 


Calculates absolute address for JR instructions and adds 
number and addresses to mnemonic. 


7A14 


Input address 


Input one address and store in memory. 


7A2E 


Initial 


Sets data at commencement of disassembling each 
instruction. 


7A3D 


Next address 


Prints next address in Hex. 


7A4F 


Octal 


Converts binary number to octal. 


7A62 


Cont RST 


Called if screen full durina decoding of RST 08 or RST 28 


7A72 


Next bvte 


prints a byte of instruction. 


7A9D 


Offsets 


Various routines to find mnemonic data. Called from conirok 


7AD4 


Control 


Master routiiie in disassembler. 


7B0B 


Transfer 


Moves data around memory. 


7B&3 


Print strfnq 


Main print routine- 


7B81 


Check finish 


Used to determine end of routine. 


7893 
7B9E 




Data for input prompt messages. 


7B9F 


Add Slrinq 


A numt>er of routine to built up mnemonic. 


7C00 
7CFF 




Data for mnemonics. 


7D00 
7DFF 




Data and data pointers for disassembler. 


7E00 ' 
7EFF 




Print data for menu and routines 


7F00 
7F1F 




Addresses of routines 


7F20 


keyboard 


Reads keyboard. 


7F56 


menu 




7FA5 


input strinq 


heart of all input routines. 


7FH) 
7FEF 


mnemonic 
strina 


holds instruction mnemonic as it is built up. 


7FF0 
7FR 




Spare 
bytes. 


7FF8 


next 


Contains next address for routine. 


7FFA 


finish 


Contains finish address for routine. 


7FFC 
7FFF 




Spare 
bytes 



78 YOUR COMPUTER. MARCH 1983 



n 



iiiiiniiiiiiiiiiiiiiiiiiiiiHiiiiiiiiiiiiiiiiiiiiHiiiiiiiiiiiiiiiiiiiiiiniiiiiiiiiiiiiiHiHiiniiin 



1 SPECTACULAR GAMES AND UTILITIES 1 

= - FEATURING FULL COLOUR AND SOUND M 



SPECTRUM16/48K 



1 TRACK N- ATTACK = 

= Shoot down the enemy carrier based helicopters using your = 
= laser beams. Complete with on-screen scoring and full graphics. = 

I SUPERSCRIPT M.P.F. 1 

S Enhance your programmes with this magnified print facility. S 
= (MPF), Features full positioning and character size selection. = 

I BLACKJACK 1 

S The classic card game (21s/ Pontoon). Full colour on screen = 
= presentation of bets, wins and debts — with your Spectrum as the = 
=5 croupier. = 



CHAR WALLAH 

Over 40 ready defined characters for you to liven up your own 
programmes. Includes — Airplanes, Helicopters, Space- Ships, 
Faces and Card-SuKes. 



I I iXE YWQRD > 



KEYWORD SOFTWARE 
31 AVENUE ROAD 
N. HAYLING ISLAND 
HANTS 



= ALL THESE ON ONE QUALITY CASSETTE FOR ONLY £4.95 INC P&P = 

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DRAGON 
PROGRAMS 

-THE BEST VALUE ON THE MARKET- 

COMMENTS ON FAMILY PROGRAMS 

"Exceltent" - M H of Bokon 

"Vorv ^njoyoWo. exceWont QuaUty" — C G of Colchester 

FAMILY PROGRAMS: Eight ru1l>»ength, oJiglnaJ games, uiiliiies and e<Juc3tion 
programs to lest your general know^edg^, memory, reattons. m«nta1 ariihmettc, 
cunning, dextenty, musicat knowledge and more. 

LOOK AND LEARN (NEW1J: Six enormcHis educational (Kograms for otder children 
and adults. Over ICOK of imtructions and quizzes on zoo animate, British towns, deseft 
suTviveL music making and includmg a tutorial on high resolution graphics. 

FUN AND GAMES: Ton ojcciting games for young and old, single players or parties. 
Include Noughts, Brain, GoW, Artdgranw. Snap, Dice, Donkey, Circles, Artist and 
Musical. 

£6 per ca^sotte (£10 for two cassettes. CIA for all threel! 

FULL COLOUR. SOUND AND GRAPHICS 

Send cheque.' PO to SHARDS SOFTWARE. 10 park Vale Couix Vine Way. 
Brentwood E»sex Cm14 4UR. 

GENEROUS DEALER DISCOUNTS 



STOP PRESS JUST RELEASED CITY DEFENCE 

fast, colour, action nfiissile command game £5-* 




BRINGS YOir 

THE PICK OF THE 

GAMES! 

GAMES- GAMES- GAMESI More and more computer gameshit 
the market every month, BUT THEY CANT ALL BE GOOD. So- let 
LEISUREMAIL short list the VERY BEST for you. Send 50p NOW for 
our big 'BEST OF THE BUNCH' catalogue. We selea TOP 
QUALITY SOFTWARE FOR YOUR ZX8I - SPECTRUM - BBC 
MICRO - GENIE 2 - VIC 20 - DRAGON 32 - ATARI etc. 

SPECIAL THIS MONTH 

New Generation ESCAPE for I6K Spectrum - voted by Sinclair 
User as 'best and most original game yet seen for Spectrum! Only 
£4.95 post paid. Simply amazing graphics. Also fabulous new 
release -3D TUIVJIMEL- 1 6K and48 K versions for Spectrum on one 
tape- £5.95. 



To;- LEISUREMAIL (YC), 69, Long Lane, London EC1A9EJ. 



S \p\€ 



S I Please rush me your BUMPER CATALOGUE of TOP FLIGHT 



§ I 
I I 



GAMES, f enclose 50p {refundable first order). 

J encloseE for . . . .ESCAPE and/or 3DTUNNEL plus 

free catalogue. OR debit my ACCESS/DINERS/AMEX 
account number 

Name> , 

Address:- 



__j 



Cassette- Based Business Software by Andrew Drane 

for 

EPSON HX-20 PORTABLE 

NEW from MST CONSUL TANTS 

STOCK CONTROL PACKAGE 

£25.00 fully inclusive 

You will wonder how you ever managed without this simple- to-operaie, 
self-contained, functionaL stock-control system. Features include 
*Hard copy on integral printer 
' Ready access to all stock records 
*Oate and time recordings of printer listings 
•Ability to store thousands of stock items on microcasseiie files 
'Menu based options displayed on integral LCD screen Software Menu 
Options include: 
Add /Amend stock, stock search, delete stock, reorder report, stock 
evaluation, stock list, amend stock levels, file exchange. 
Also EPSON HX-20 DATABASE. SUPER-CAPACITY card index system. 
Choose your own headings. Facilities include sorts, searches, field totals 
etc. £25 inclusive. 

DRAGON 32 PACKAGES - available NOW 

MST DATA — Card Index filing system. C19.95 inclusive. 

MST INVOICES and STATEMENTS - Prints excellent and 

detailed documents, etc, G19.95 inclusive. 

MST STOCK CONTROL - Stock lists, stock evaluation, Reorder 

reports, etc. CI 9.95 inclusive. 

MST BUSINESS ACCOUNTS - Debtor/ Creditor details and 

summaries, etc. on printout. £19.95 inclusive. 

MST MAILER — Dedicated database for formatted address 

labels etc. £19.95 inclusive. 

Each program comes with descriptive leaflet, operator notes, etc. 

Each customer will receive details of our hot-line link. 

Cheques and Postal Orders should be made payable to MST 

Consultants. Fully-inclusive prices include VAT and postage costs. 

Send your remittance to: 

TRADt INQUfRIES WELCOME VAT REG NO: 36$ ftbyS-O? 

MST CONSULTAPdTS 

Newton Road, Bovey Tracey, 

Newton Abbot, South Devon TQ13 9BB. 

Tel: 0626^832617 



YOUR COMPUTER, MARCH 1983 79 



GET THE BEST NEW PROGRAMS AND THE 
ALL-TIME GREATS, SPECTRUM OR ZX81 

AT SOFTWARE SUPERMARKET NOW 

We started Software Supermarket with just one idea. To play aU the 

Spectrum and ZX81 games we could find, to select the very best, and 

to offer only those to our customers- 
Judging by our mail from aO over the world, you're very pleased 

with our free selection service. It s impartial (we produce no programs 

ourselves) and it saves you £££s on stamps and mistakes. 
And it's fast. We usually despatch your order within 48 hours. 

Here's the best of the new and the best of them all for your Spectrum. 

Plus some great ZX81 games. Full detailed catalogue sent free with 

every order. Or send large SAE for catalogue only 




mmrnmmmmm 



Our latest Top ID Programs for your Spectrum. They run on both 16 & 48K. 
^1\ 1*fff1II1IT17f Brilliant NEW 3D graphic game by Malcolm 
OU I U N 111 Cili Escape" Evans . Fly down the v\1nding 3D 
tuTJiel shootmg bais. spiders, frogs and rats! Demo mode: 3 speeds: trainiBg 
program for each phase. And {48K only) watch out for the Tube uam! 
(N€wGeneianon)C4.95 

A v% m A M V ^^^'^ 9^^® ^'ith stunning graphics. Shoot the 
vU E nN £m enemy from your 3D tank turret. 3 play levels : accurate 
ballistics: 1 or 2 players: hold feature: demo mode: training program. And 
choose your own control keys: even plays 'God Save The Queen' 
(DKTronics) £4.95 

WINGED AVENGER a^f^^e^^^o/tA^r^de 

ongma!,..a game to come back to. 'Pop.Comp.Wkly. Very fast ?HOENDCV 
7 play levels- 3 attack waves- laser shield: modieiship with smart bombs. (Work 

force) £4,50 (i6:< ZX81 version. C4,d0} 

#« U f\w r KI1\ A T"P A r*lf *^^^ Spectrum version of 
UnwUiHi/ A A In%#Ik the arcade game" Yr:Comp: 
Vmy ai^oibmg' E&C Extremely good " Pop.Comp: Wkiy rnrillmg 
SCRAMBLE'. Pilot your ship thro' 26 zones: up. down, brake, thrust: smart 
bombs: as you get belter it gets harder. (Silveisoft) £5.95 
#iin|||i|i v|||-«^|-i T}ie first - and fast - Spectrum version of 
wulll JL llr JCil/lSi the famous arcade game Full arcade 
movement - ten. right, up. down, fire - as you attack the centipede. Great 
graphics. Watch out for the jumping spider! 3 lives: hold feature. 
(DKTronics) £4.95 

|-i M #ir j| nc* Orte of the b^t and most original games we have 
J!i0 wnlr u seen " S User. 5 very real dinosaurs chase you round the 
maze as you search for the axe to escape. Different maze every time. 5 play 
levels: 9 speeds; Hall of Fame. (New Generation) £4.95 

VI U Milr Ilflnlll exceptional progiam, " PopComp: Wkly 16 mazes, 
each with demo mode: 9 speeds: laser gun helps against 4 chasers. Program 
your own control keys personalise/save your very own game. (Campbell) £5.95 
^^QHJI^M NEW' Fantastic graphics. Loads in 2 parts 
w%/91¥l Wm (mstruction manual first). Protect your 9 ships against 
18 aliens, warp mmes. asteroids. Your graphic on-board computer helps with 
elaborate displays. Our favourite new game. (Abbex) £4.95 

wm A f f G'P'C l?rtT ¥ V '^^ *^^^^ adventure we've seen 
It nUd 1 M It \/1j1jX ihai's worth playing in 16K. It's great 
and It's got graphics! Loads m two paits: clear instructions first. Then a 
smashing adventure with directions, inventory, look, score, save. Amazing^ 
Abbex) £4.95 

U 1 Oliiulj^ opponent' Yr.Comp. The great 19th Century power 
game. Surround your opponent: capture his tenitory. Millions of different 
games: maximum 60 moves each. 1 or 2 players: demo game: 9 skill levels: 
print. (Mol) £7.95 



S^^edal iSK ZX81 versions of 6 of these programs are available: 



WINGED AVENGER £4.50 
OTHELLO £6.95 

BLACK CRYSTAL £7.50 



PMANIA £8.00 

CHESS 2 £9.95 

GREAT BRITAIN LTD £4.95 



Ir.ese programs use nearly aii the Spectrum $ 48K. They wiil not lun on ihe loK 
Spectrum. But there are versions of Black Crystal. GB Ltd, Pimania and 
SpecChess for for 16K ZX81. 

Df Hil A lUTI A ^^ ^^ adventure game we have reviewed" 
It Alwlnllll A S.User "An adventure enthusiast's dream'^C&V 
Games. Best use of Specuum graphics and music we've seen A wonderfully 
witty adventure - and you could win the £6.000 Golden Sundial of Pi. 
(Automata) f:iO (ZX81 16K version: £8) 

TTR/ll?^ A TIT "^^ ^^ graphical game I have seen on any 

M XIwIuUA A & micro" Interface. "Excellent graphics.,. one of 
the best " Yr:Comp: Tast and furious ..required joying for any Spectrum 
owner" Which Micro? 5 skill levels: training program: Hold: Hal! of Fame: 
keyboard overlay: 26 page on screen manual: (Quicksilva) £6.95 
in vjlji 0/\llll IT 'Superior to any other adventure game 

I lUL fll/D01 1 available for the Spectrum'' YrComp: 
Free 285-page illustrated book of The Hobbit contains clues to help solve the 
adventure. 30 beautiful fuU-screen pictures: 500 word vocabulary: 16 page 
insliucuon manual: save: print: pause. It took 4 people 18 months to write' 
(Melbourne House) £'4 95 

GREAT BRITAIN LTD^^'^<^ 

management game" Pers.Comp v,':d. Difficult and challenging" ZX Comp: 
Even plays 'Rule Britannia' ! Choose your party and ran the country. WiU inflation 
and unemptoyment come do^sTi or the rioters come out? It's up to you. Then 
watch the results on election night! (HesseU) £5,95 (16K ZX81 version. £4.95) 

mIt JCi\#l#nl!idd strongest chess program" Pop:Comp:Wk!y 
Full graphic chessmen: 7 play levels: all legal moves: position analysis for 
problem-solving: recommended move option: print game history. (Artic) £9.'45 
(ZX81 p.on-graphic 16K version £9.95) 

»jf Af^V r^llVCPAf '^ake the adventure of your life 
0Ijrli#Im i#Il X 1 nil IBOK of program to unravel on 
two double-sided cassettes^ You must solve each of the 6 stages to defeat the 
Lords of Chaos. Real-time monster battles: 16 command keys. [CameU) £7.50 
{16K ZX81 version: Over lOOK loads m 7 parts £7 50) 



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Computer 


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AND 

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80 YOUR COMPUTER, MARCH 1983 



The first demonstration program. 





1 



2 
3 
4 
5 
9 

10 

20 



GOSUB40 

DflTfl225. 231 . 235. 240. 

203. 219. 225. 232 ..225. 231. 235. 

240. 215. 223. 228. 235 • RESTORE 

F0Rfl=lT04 

F0RB=iT04 

REflDBCft.B> 

NEXTB.fl 

P0KE36878. 15 

DIMC<4.4).D<4.4> 

DFlTfll95. 215. 195.219.195. 

221.195.219 



VIC-20 



21 DRTfl209.225.209.228.209. 



22 
23 



24 
25 
26 
27 
28 
29 
30 
31 
32 
33 
34 

35 

36 
37 
40 
50 
60 

70 
71 
72 
73 
74 
75 
7S 
77 
78 
79 
80 



229.209.228 

DflTfll95.215. 195.219. 195. 

221.195.219 

DRTfil 75. 201. 175.207. 175. 

209.175.207 

REM*************** 

FORR=1T04 

F0RB=1T04 

RERDC<R.E).D<R.B> 

HEXTB.R 

DEL=220 

F0Rfl=lT04 

F0RB=1T02 

F0RC=1T04 

P0KE36874.CCfl.C> 

P0KE36875. LCfl. C> : P0KE36876. 

B<fl.INT<RNDCTI>*4+l>> 

F0RB=1T0LEL •' NEXT - P0KE36874. 

0:POKE36875.0 

NEXTC.B.R 

GOTO30 

P0KE36879.8:PRINT":a5| THE 

PRINT" " 

PRINT"Wia BV: " :PRINT"MaBlR,mC IELINSKI 

PR I NT " fmmfmmsmmn^wnr ; 



GOSUB70 



VIC 




: PR I NT" 
" - RETURN 



IFC=1THENPRINT" 
IFC=2THENPRINT" 
IFC=3THENPRINT" 
IFC=4THENPRINT" 
PRINT'TTTTiiWI" 
IFC=1THENPRINT" 
IFC=2THENPRINT" 
IFC=3THENPRINT" 
IFC=4THeNPRINT" 
RETURN 



•Mil ii3) 91 nmnA »«llt^ 
^rNSsMiis) sail I 






I 

\"; 
I "; 



•mi/'si 

Mil • 

•mi/'Si 



)iiii|i i£i SI )!]iiii Si ■ mil I t 
immwm \^ 91 ami si ■ isubi i i 



''^[/t)U> Z^^S^^ 



These driving barrelhouse 

boogies, penned by Adam 

Maclelinski, take you for a 

stomp through the Vic's 

three music channels and 

show you how to 

orchestrate a full 

polyphonic sound to suit 

your musical tastes. 



PLAY THAT BOOG 



The VIC has three sound generators: one bass, 
one tenor, and one soprano. Each generator 
can be used independently or together. Most 
of the timCj only one, or even two generators 
arc used. One good example of two sound 
generators working together is in Bug-Byte's 
Vicmen. 

Here we shall delve in to the art of using 
three sound generators at the same time 
without creating discords. People with a 
musical ear should understand the method 
used very clearly. The method adopted is to 
set up a fixed left-hand section of the keyboard 
using the bass and tenor sound generators. 

The notes for the left-hand voices are stored 



19 HERE ARE SOME OF TIC CRflPHICS FIND CONTROL 
2e C^4AR«CTERS USED IH THE PROGRAM 



30 
50 
€6 

re 
75 
77 
78 -di' 
rs -■■ 

99 • 

199 
119 
129 
139 
140 
158 
1^9 
179 
188 
190 
200 



ir 

w 



w* - 
■" - 
-ir 
"a* 

■ r 



COURSOR rtOUN 
CURSOR UP 
CURSOR RIGHT 
CURSOR LEFT 
CURSOR HOME 
Cl-ft 

REVERSE DM CCTRL ♦ 
REVERSE OFF CCTRt 
WHITE CCTRL ♦ 2) 
BLACK (CTRL * 1) 

- GREEH CCTRL '^ 6> 

- VELLOW CCTRL ^ 8> 

' COHHODORE LOGO + KEV A 

- CONnODORE LOGO 4- KEV B 



K£V9> 
K£V9> 






- COrtlODORE 

- COMMODORE 

- COMMODORE 

- COMMODORE 

- SHIFT 4^ H 

- SHIFT ♦ n 

- SHIFT ♦ Q 



+ KEV L 

♦ KEV M 
+ KEV T 

♦ KEY 



in a Dim statement. To make the left-hand less 
boring and monotonous three different keys 
have been used, but the chord played is still 
the same. Therefore a total of 12 different 
notes will be stored. In the first demonstration 
program — which includes a humorous ani- 
mation — the set of chords is played twice and 
the third chord is in the same key as the first 
chord. 

With each key played, four notes may be 
played to accompany the left-hand chords. In 
the key of C-major the notes for the right-hand 
are as follows — the right-hand column gives 
the value in the Vic manual. 

(continued on next page) 



YOUR COMPUTER, MARCH 1983 81 



(continued from previous page) 

Note Value 

C 225 

E 231 

G 235 

topC 240 

In both demonstration programs the right- 
hand notes arc handled by a Dim statement 
and are played randomly by using 

lNT(RND(TnM) + l 
The TI ensures that a totally random number 
is produced. This method then produces a 
totally random tune together with the main 
left-hand chords, using all three sound 
generators. 

The second demonstration program uses a 
more complicated set of chords which 
produces a mixture of two or three sound 
generators going on at once. This is because 
the first four notes in the left-hand Dim 
statement were ail more than 0> whereas the 
rest of the Dim contained half Os and half 
proper notes. This creates an interesting effect 
and the contrast between two-part harmony 
and three-part harmony shows well. 

With a lot of experimentation — unless you 
have a piano or a similar instrument — you 
could produce your own tunes and left-hand 
chords. Perhaps you could even add a little 
white noise to the tune to give it an alien, 
sinister quality. 

I would advise against turning up the 
volume too far: quite apart from the 
neighbours, the faithful old TV cannot stand 
the wear and tear that multi-harmony tunes 
can produce. So just remember to play it cool. 



The second demonstration program, 

1 DIMft<4.4).BC4.8).CC4.8> 

2 DfiTfl225. 231 . 235. 249. 209. 219. 225. 232. 225. 231 . 235. 240. 215. 223. 228. 

3 F0Rfl=lT04 

4 FORB=1T04 

5 REflDfl<fl,B> 

6 N£XTB,fl 

7 F0Rfl=lT04 

8 FORE=1T08 

9 REflDB<fl..B>,C<fl.B> 

10 NEXTB^ft 

11 DflTfil95>215,195.215.0,203>0.207,8.215,0,215>0.203,0.207 

12 DflTfl209. 225, 209, 225, 8, 217, 8,219,8, 225, 8, 225, 8, 21 7, 8, 219 

13 DFlTfil95, 215, 195,215,0,203,0,207,0,215,8,215,0,203,0,28? 

14 LftTfll 75, 201, 175,201,0, 187,0,191,0,281,0,281,8, 187,8,191 

28 P0KE36879,8-PRINT"an VIC BOOGIE 11" PRINT" .. i_^_ .' 



21 PRINT"WWBV: " :FRIHT"M«iFl.MflCIELINSKr'-P0KE36878, 15:DEL=150 

22 PRINT"MWHttiaWMttftai«ail^ " 

23 PRiNT"»»Dai(»nu»nunnia>Mwi4:) nitxDsiid ■" 

24 PRINT "W!)IU»)!l«I«HUnuni^ 

25 PR I NT " »innixKn!inN4vjnffNiii nii nil [ai mi rrmirnRiirna jiira " 

26 PRiNT"»(«KDan«ninH»ffii«i^ bin" 

30 F0Rfi=lT04 

31 F0RB=1T02 

32 F0RC=1T08 

33 P0KE36874,B<fl,C) 

34 P0KE36875,C<R,C) 

35 P0KE36876 , fl < fl , I NT ( RND < T I> 3|c4+ 1 ) ) : eOSUB40 

36 F0RF=1T0DEL:NEXT 

37 P0KE36874 , 8 = P0KE36875 , 8 

38 NEXTC,B,fi 

39 GOTO30 

40 PRiNT"»nnuDa]iHi4n»n»>»>>»ir'; 

41 IFC=10RC=5THENPRINT" • / SUIllll Sl ■ )lllllll I « 

42 IFC=20RC=6THENPRINT"» _ aillllSl ■ XIHIN \ " 

43 IFC=30RC=7THENPRINT" t /lAIIHI S) ■ aillll I I" 

44 IFC=40RC=8TKENPRINT" • I Ulllll ^ art)!»lll»n / /" 

45 RETURN 



Battle of Britain 

By Microgame Simulations for the Spectrum 

One day \n summer, 1940, Reports are coming in of enemy 
bomber squadrons crossing the English coast; target unknown. 

How are you to deploy the nine fighter squandrons under your 
command to intercept the incoming threat! 

British and enemy squadron movements are plotted on a superb 
high resolution secreen map of south east England with 
communications signals presented both visually and in morse 
code. 

Features variable difficulty levels, full control of squadron 
movements, randomly selected targets and bomber routes for 
each game, intelligence reports, refuelling etc. 

A tense game of strategy for one player. 



48K Strategic 
Wargame 




only £5.95 
(inc. pd-p) 




SOFTWARE FOR BBC 
TRS-80 AND GENIE 
from DAVANSOFT 



Win th* Poofs? 

With the latest version of S Peckett's well-known Poote Prediction progrsm. Now 
available for BBC Micro (needs 32K memorv'J »« w«ll as th« TRS-SO {LI I J and Video 
Gonie. 

Prog fa m and instruct ions £4.95 

Database tape (optional, but tl3.S0 

holds d^tii on over 6SO0 rrvatches) 
Program and 08 toegtKer £17.50 

baby PILOT 

Easy-to-use, triertdly af>d very fast version of this important teaching language. 
Nformal PILOT commands PLUS arithmetic, graphics, loops and other extra featues. 
baby PILOT (TRS «l and VG onty» C9.95 

TRS-eO/VG Shift Lock 

Avoid the irrhatton of holding-down the shift key to entftf lower-case. Adds 2 new 
commands to Level tl BASIC to make the keytx>8rd work like a typewrfter, or switch 
back to fKKmal. 
Shfft-Lock ^must have I'cdse h'ware} £3.d5 

BBC Olsastembler 

Now - A fun 6a02 disassembler, with automatic labeWng, and with the ability to avoid 
data areas. Optional dumps to printer and/or tape for later study, modification ^n<i 
LOADing. 
BBC Disasswrtblef £5.95 

BBC Character Builder 

Makes it easy to re-deftne characters for the Beeb's VOU Z3, command. ^Create 
characters on the screen and save them directly ds lines of program — essential to the 
keen B8C pfogramnrief. 
Character buifder £4.96 

BBC Tape-Copy 

Worried that you cannot make safety copies of valuable BBC machinenrode tapes? 
This program will back-up any standard format machirte-code tape, comptete with start 
address, etc. 
Tape-Copy (32K onlyj 0.60 

All these prices are futly inclusfve and are for cassette -based programs only. 

DAVANSOFT 

1 Delapoer Drive, Haverfordwest, 
Dyfed, SA61 1HX 

We are always looking for high -quality programs for TRS -80, VG and BBC com putters, 
and will pay up to 30% royalties for suitsbfe material. Please contact us with your 
proposals or for details of our requircrr^ents. 



82 YOUR COMPUTER, MARCH 1983 




More memory for your ZX81! 

ZXPANDA. 

The uniquely expandable 16K RAM pack 

The professionally produced 16K RAM Pack 
that is expandable to 32K simply by 
plugging-in our expansion module. 
Start with 16K . . . expand later to 32K! 
Solidly built, attractively cased to fit 
perfectly on to a ZX81 without wobble! 
Includes LED power indicator. 
The RAM pack that won't become 
redundant when you want more than 16K! 

16K Expandable RAM £32.95 

16K Expansion Module £19.95 

M ore sound from your ZX Spectrum! 

Echo 

Not only more sound, but better sound and a wide range of 

other facilities! 

Control Volume, and adjust tone of sound! 

Load and Save without switching leads! 

Audible cue facility for tape programs! 

DIN compatibility! 

No additional power supply needed ! 

Attractively cased- looks good 

- SOUNDS GOOD! 

Only £23.50 



More memory for y our Jupiter Ace 




Pacer 

The uniquely expandable 

16K RAM pack 

Similar concept to ZX-PANDA but for 

the incredible iupiter Ace. 

Attractive, solidly built 16 K RAM pack 

with the facility of expanding to 32K 

by plug-in module. 

For more power to faster FORTH . . . 

you need a PACER! 

16K Expandable RAM £29.95 

16K Expansion Module £19.95 



C 



O 



T 



sTONDoci* cxcmcracs 






More memory for your VIO20 

Vixen ram cartridge for the VIC-20 

Switchable between 16K or 8K + 3K. 

Gives you the option of full 16K RAM or 8K and 3K RAM in one 

package. When added to a Standard VIC-20 

gives 16384 bytes of extra memory in 

memory blocks 1 and 2 or 

3092 bytes of extra memory 

into the 3K memory block AND 

8192 bytes of extra memory 

switchable between memory 

blocks 1 and 3. 

Fully compatible with available motherboards/ modules. 

Simply plugs into the rear expansion port of computer. 

No readdressing of existing BASIC programs needed. Only £44.95 

Tandem 

Expandable Expansion System for the VIC-20 

Gives 4 expansion slots for VIC-20 cartridges. 

Custom-designed case. Plugs directly into 

computer. Further expanded 

by using TANDEM System! 

ROM socket for expansion. 

No extra power supply needed 

Only £34.95 



r 

■ Aid 




: Stonectilp Electionics, Unit 9, The Srook Industrial Estate, De^dbrook Une, 
Atdershot, Hants. Telephone: (02S2) 318260. 
Please forward me the following products: 



All pric^ are indii$i>« of VAT, Post & Packing tor U.K. deliveries (overseas add 15%) 

Name: ...*... 

Address: , 



STONECHIP 
ELECTRONICS 

"more ways to make more of 

your computer" vl 

DEALER ENQUIRIES WELCOME Delivery approx 14 days 

YOUR COMPUTER, MARCH 1983 83 




Figure 7 


. A fisting of routines used in the 


machine code with the Start addresses. The 


machirte code is in the form of a decimaf 


dump in 


blocks of six bytes with the Start 


address of each block given. 


Start 




address 


Routine 


29666 


Check and accept 0-255 and Print 




keys pressed in Input lines* 


29859 


Pause unti! key pressed. Uses Halt 




command. 


29871 


Check last key press. 


29900 


Check number selected with menu 




options 1 , 3 and 6. 


29951 


Main typewriter calls for un-shifted 




and single shifted keys. 


29971 


Double-shifted key calis. 


29978 


Print 8 x and 1 x size redefined 




characters. 


30076 


Print Spectrum and "new" redefin- 




ed characters. 


30157 


Print "decimal-number" prompt. 


30182 


Print screen format for Redefine 




Mode. 


30364 


Print instructions routines. 


30774 


Data for sub- menu. 


30821 


Restore character mode in use. 


30831 


Print sub-menu. 


30855 


Data for menu. 


30986 


Print menu. 


31013 


Set screen and input tines bright. 


31027 


Erase-a-page start. 


31038 


Next page. 


31067 


Data for double-shift alternative 




character set. 


31083 


Store character mode in use. 


31097 


Normal and single-shifted key calls 


31177 


double-shifted key check and calls. 


31214 


Justify. 


31242 


Erase part of a page. 


31293 


Find cursor. 


31316 


Rubout. 


31350 


Justify subroutine. 


31493/4/5 Spare. | 


31496 


Data for Justify. 


31500 


Insert/delete. 


31599 


Spare. 


31600 


Find page. 


31624 


Erase a complete page. 


31636 


Print a page. 


31664 


Squeek. 


31684 


Buzz. 


31710/11 


Spare. 


I 31712 


New character set codes. 


32481 


Set parameters of page to be 




printed and call print page. 


32489 


Spare. 


32490 


Tap. 


37B00 


Check character to be plotted. 


32534 


Plot character. 


32573 


Set Spectrum character mode. 


32580 


Set new character mode 


32587-91 


Spare. 


32592 


Set Over 1 for cursor. 


32600 


Piot cursor. 


32651 


Data for cursor position X, Y top left 

= 1J. 

Cursor handling for Newline, 


32653 




Space, and put character plotted in- 




to x$ array. 


32682 




32767 


Cursor keys check and move as re- 




quired. Uses In function to read 




keys being pressed instead of Peek- 




ing Last Key 23560. 


Data 




31616 


Page number in use. 


32501 


Character code of key to be Plotted. 


31529 


Number of characters to be inserted 




or deleted. 



This program for the 16K Spectrum started 
out as a straightforward typewriter program in 
Basic with approximately 30 bytes of machine 
code to plot characters on to the screen in such 
a way as to give 42 characters per line. But the 
program was slow and used too much RAM, 
leaving Httle free for data storage. 

The solution was to convert all the routines 
into machine code and maintain a minimum of 
four pages of data with 42 characters per line, 
this being the equivalent of five and a quarter 
pages of text if the normal 32 characters per 
line were used. 

Up to this point I had been using the 
Spectrum character set, but the upper-case 
letters were touching each other and making 
the text illegible. I added a new character set 
with ail the characters redefined on a six-by- 
eighi pixel format. This created the option of 
using the Spectrum set or the new typewriter- 
mode set. 

The program starts with the main Menu, 
which has six options. 

The Start option takes you into the type- 
writer mode. It begins by asking for the page 
required and printing the selected page. This 
is done to avoid accidental overtyping of an 
existing page of text. A cursor is placed in the 
first character position at the top left of the 
screen^ and can be moved to any position by 
means of Caps Shift and cursor controls; keys 
5-8. 

The cursor always indicates the position of 
the next character to be typed. If the cursor is 
moved over existing typing the character will 
change to white Ink and show through the 
cursor. If a character is overtyped, then it will 
be printed on top of the existing character, but 
the last character typed is held in the memory 
of the computer. 

AU Spectrum characters are available, using 
Shift keys as necessary, and all but the double- 
Shifted ones arc auto- repeat. 

Incorrect entries can be quickly erased by 
the use of Caps Shift and Delete. This will 
erase the character behind the cursor and 
backspace the cursor over the deleted 



character. At the start of a line it will erase the 
last character on the previous line and 
backspace on to that line. This function is also 
auto-repeat. 

A Newline is obtained by pressing Enter, 
and this function will also auto-repeat. If the 
cursor is on line 22 then Enter will move the 
cursor to the end of line 22 where it is split 
into two, bracketing the last line, to indicate 
that the end of the page has been reached. 

This method is used to erase the last 
character on a page, the cursor being in effect 
after the last character. There are several 
options available in this mode and, as a guide, 
these are indicated on line 24, wnth the keys 
necessary for each option shown in inverse 
video. The next options require both Shift 
keys to be pressed before the option letter. 
First, n(cxt) will scroll the page oil the screen 
and replace it with a copy of the next page. 
This can be used after finishing typing a page 
or to read through the pages. If you are on 
page 4 then the next page will be page 1'. 
Second, m(enu) will take you back to the main 
Menu. Third, z is the copy key and, as it 
suggests it will copy the page on the screen to 
the printer. 

A further facility is the Edit mode. This is 
accessed by Caps Shift and Edit, and when 
selected will give you five options. These will 
be printed on line 24 of the screen with the key 
presses for each option shown in inverse. 

Insert — when selecting this option the 
cursor must be over the first character in the 
block to be Shifted right. You will be asked 
how many characters you require .to be 
inserted; this must be in the range 0-255. The 
decimal number can be entered either with 
leading zeros like 032 or 006, in which case the 
Spectrum will atuomaiically accept the 
number without the need for Enter, or as a 
**normar* number, that is, 32 or 6, in which 
case, if it is less than 100, the use of Enter is 
required. Each key press is checked, a buzz 
will sound if the entry is not valid and three 
questionmarks will be printed, A zero entry 
will skip this routine. 



The Basic program. 



THEN GO 



INPUT 
PEEK 3 



lO POKE 33696^1: RPNDOMI2E USR 
3iei3; DIM x^f4..934.^: LCT M *« : 
UET I aS« : L-ET v od3SeO : l^ST 
a: GO TO » 

yp =?RNE>OMlZE USn 31083: 
iNKCYf: PRINT mc:"Pa9e f" 

SS RRNODMIXE U31R 3oRaa 
GO RRNDOHXZfT U3R 2S951 
14© IP PECK V=7 RIstO PECK 3Sie51< 
yd.3 THEN GO TO 7©« 
ISO IF PEEK v<>1.4. THEN GO TO ft© 
ISe RRMOOMIZE USR 29971 
230 IF PEEK V=rCODe "n" TMEN RRN 
DOMIZE USR 3XfS3Q: GO TO ^ 

ase^ ir f^c:&< v^cooe: "m" tm^n c5o 
TO • 

a*7«l GO TO ttO 

64.0 RRNOOMiZe USR 3ia03; INPUTT 
XMKCVf; PRINT ttx;-MOU MRNY CKr&. 

•? "; 

370 RRNDOMJ2E USR 29666: RRNDOM 

I2E USR 30S21: IF PEEK a96S4.:=x T 

HEN GO TQ "TBO ^^ 

Geo mwiO^mX-E^ USP 315««: GO TO 

-7x5 RF1NDOMI2E: U6R 3i0e3 r INPUT 
INK^y*: PRINT nx}'jm»%t^f I :B^l^l^ : 
— -ase ; UUSTIFXB^ L/p^ 

?30 RRNOOMXZ^ USTJ. 3a©21 : PRUSE 
X : IF PEEK V =CODE ' i • THEN POKE 
31S4d^IQ: GO TO S40 

74.a IF PECK V-COOe "d" THEN POK 
C 3IS4-4.,X: GO TO 54-0 

7SO ir PECK v>CODC "e" THEN RRN 
C'OMIZE USR 3154.2^ GO TO 7SO 

?6a IF PECK V kCOOC " I " THEN POK 
C 314.12^79: GO TO 8000 

^TO IF PKEK V sCOOC " r ■' THEN POK 
C 3XA13,X: GO TO eOOO 

700 RRNDOHZZC USR 32692: GO TO 
t 

100O 
I 
2900 

r*oxo 
:SQ&9 



GO 



PRU&C 



^7: 



RRNDOHIZC USR 29900: GO TO 



RRNDOHZZC USR 30434: 

GO TO m 

RRNOOHIZE USR 299IS 



STOP 



3020 IF PCCK V >CODC ' 

TO m 

30S0 RRNDOHIZC USR 30S4S : 

S020 

4-000 RRNDOHIZC USR 30GiS: INPUT 

i * 

4O10 PRINT RT ll^x ; •*SftUING t ; 

i «; " " " DRTR X » t J ■• : SftUE i $ DRTR 

ic $ t > ■ GO TO 502O 

SOGO RRNDOMIZE USR 30G74 : INPUT 

S010 RRNOOHTZe USR 30720: 
X : LORD i « DRTR X $ f i 
5020 RRNOOHXZe USR 307S6 : PRUSC 
K : GO TO m 

5000 RRNDOHIZC USR 29927 
6030 IP PCCK V-CODE "1" THEN RRN 
DOHXZE USR 32573: CO TO Vt 
6050 IF PECK VmCODE "2" THEN RRN 
r>OMTZE USR 32Sa0 : GO TO W 
to©5S RRNDOHIZC USR 3020O 
6060 INPUT i % 

&O80 IF LEN i»>l OR i*<" '* OR i$ 
>*'^- THEN RRNDOHIZC USR 31684: Q 
O TO 6060 

B085 POKE 30177^ CODE i* 
B090 RRNDOHIZE USR 30076 
S100 FOR b"l TO S 
6110 RRNDOMT7E USR 301S7 
S140 RRNDOHI2E USR 29666: RRNDOM 
-^35 »JSR 29^73 NEXT b 
6190 PRINT nx,-'0-K_? BCpeAl ; 
OtH<tr Keys MENU": RRNDOHIZC USR 
30B&1 PRUSC x; IF INKCY»»**r" TH 
l£N CUS : GO TO e0SS 

nao© GO TO m 

S00O RRNDOHIZC USR SIOSS: INPUT 
INKEY*: PRINT Itx; j9*9^ OR »UfSor 

I i ns '?" 
3020 RRNDOHIZE USR 30S21r PRUSC 
^. ■ IF PCCK V =CODE "€*' THEM RRNDO 
tlXZei USR 31i^24 GO TO I 
©030 IF F*EHK V3=CODC "P" THEN RRN 
DOMIZE USR 3132S: GO TO I 
0040 GO TO 7aO 

900O RRNDOHIZE USR 29939: GO TO 
1S3 fr (PCCK V -48) 

^300 CLEAR 3966S LORD " "CODC 29 
£66: GO TO X© 
9900 SAUC "t,yp«" LINE 9SO0 : SRUE 

" -CODE 2964^6^ 3 103 



84 YOUR COMPUTER, MARCH 1983 



The maximum number of characters that 
can be inserted is one less than ihc number of 
characters from the cursor to the end of the 
page if this is less than 255. 

Any character pushed ofT the page by this 
routine will be lost. After a number has been 
accepted the page will scroll off the screen and 
be replaced instantly with the modified page 
and the cursor, still in its original position, so 
that the required information can be typed in. 

Delete — this option is similar to Insert in 
that the cursor is placed over the first 
character in the block to be deleted, and you 
will be asked how many characters you require 
deleting before the page is scrolled off the 
screen and reprinted with the correction made. 

The Erase option will erase part of a page 
reaching from the end of the page to the line 
below the cursor. So the cursor must be placed 
on the last line of typing that you wish to keep 
before this option is called. The erased part of 
the page will scroll up and off the screen; the 
retained part stays in position. 

Justify — there are two Justify options, with 
both you have a further choice of justifying the 
whole page or the cursor line only. So if only 
the cursor line is required, be sure to place the 
cursor anywhere on the required line before 
this mode is selected. Justify left will scroll the 

VVC«D6 
CNJhE 



SPKTRUM 



page off the screen and reprint it with the line 
or page shifted to the left-hand margin. Justify 
left/right will scroll the page off the screen and 
reprint it with the line or page shifted left and 
the space between words padded out so that 
the last letter of the last word in each line is at 
the right-hand margin. 

These last options can be skipped if the Edit 
mode is accidentally selected by pressing any 
other key. The Edit mode cannot be selected 
with the cursor at the end of the page. 

The Stop command stops the program with 
the usual report and a message that "Continue 
will restart at Menu*'. If the program is 
broken then Goto 9000 will also restart at the 
menu* If Run is used then all existing typing 
will be erased. 

Now's the time to 
tackle that long- 
deferred oeuvre 
with Stuart 
Nicholls' 
fast machine 
code word 
processor 



The Erasea-page option will ask which page 
is to be deleted. Any choice other ihan 1-4 will 
take you back to the menu* The page selected 
will be instantly erased. 

Pages can be Loaded and Saved on tape with 
appropriate options. You will be asked to 
name the pages when Loading and Saving; the 
usual rule of 10 characters maximum applies. 

The Change-typeface option will give you 
three options: Normal, New and Redefine. 

Normal gives typing with the Spectrum 
characters, but because of the squashed look of 
the eight-by-eight pixel format, certain 
characters will look odd. 

New: because of the problems outlined 
above, a new keyboard has been defined to 
give a six-by-cight character set. When this 




Figure 2. 

• o.©o>o,o^©^o^o. 

$ m ie^*5S,o0^»e.2o, lae. le-©^ 

'A ■ 0. 10©, 104. .16.4* .76 -©,0, 

^ t» 3a^60>32^64... 72.Sa>6,.0.. 

' • le^ i©^0^0^0^0>0>0^ 

} = 32^ 16^ l&^ l&^ ie>3£^0^0, 

* -r. 0^40,16^124^16^40.0^0. 

J 3 0^0^©^©^ 8^e^ 16 ,0^ 

- » 0,0^0^ 1&4 j©«0^0^0^ 

» ^ 0^0^©^©^ 16^ 16^0 .0^ 

/ = ©^4^8, 16^3e>64,0.0^ 

» Se^76^84..84, leO^Se^©.©^ 

1 ^ 16^48,16, le, 16. S6, 0^0, 
5 ^ S6,6a,S> 16^32^124, 0,0. 

3 o 1S0>4,56.4^4. 12©,©.©> 

4 » 64>7S, 7e^lS4, &,&.©,©, 

5 a 124,64, aS0. 4 ,4, 1^0,0,0, 

6 » 56,64, lS0^ea,69>S6. 0/0. 

7 I- ia4^4, 4,6. 16.32,0.0^ 

8 = 56, feS.SS, 6©, 68-1^6.0,0^ 

9 K 56,68^63^60.. 4 ^:^6 .0 .0. 
-• =: 0, 16,16,©, 16^ 16,O^0, 

; = ©.16.16,0,16,16,35,0. 

< = O, 16. 32,64, 3S, 16,0 .0, 

" » ©,0,lg4,0. 1S4,0,O>0, 

> *» 0. 16,8^4.8 . le?, 0.0, 

? = 56.68.8.16,0.16.0.0, 

& - 56.76,84,92,64,56.0.0, 

rt -I 56,68,63, lS4,6e, 68, 0,0. 

8 * 120^63 . 120>6©^e8, 120. 0.0, 

C = 86,63,64 .64 .68,56,0,0, 

» lfi0, 66, 6^, 68, 68, 120,0,0, 
E « 124,64, 120.. 64.64, 124^. 0.0- 
F « 124,64,120,64.64,64,0,0,. 
G - 56, t>8. 64, 92, 68, 36, 0.0, 

H - 68.68.124,6^,66.68.0.0. 

1 = 56. 16. 16. 16. 16., 56.0^0. 
U = 28.8.8.8.72,48.0,0. 

K - 72,60.9e,80^72.,68,O,0, 

L ^ 64.64,64.64/64, 124,0,0, 

n *. 68^ 108. 84* 68, 68, 68 .0,0. 

N ^ 68.100.64.76,68.68,0.0, 



O = 56 .68. 66. DC 68. C6- 0,0, 

P ■ 120 , 63 , CO . 120 , 04 , ti4 , , , 

3 56.68.68,68.84.56.4.0, 

R = 120,68.68.. 120.72.68.0^0^ 

5 m ?^6.64.G6.4.68.1>G,0,©. 

T • 124,16.16.16.16,16,0.0, 

M = eo.68.ec.6e,cs.c6,o,o,. 

V m 60^68,68,68,40,10,0,0^ 
W • 68.68,84,84, 108.40. 0.0, 
X « 68,40,16,16,40.68.©,©* 

Y » 68,40,16,16,16.16,0,©. 
Z • 124.8,16,32,64,124.0,0, 

t » 48.32,32,32,32,48,0,0^ 

\ X ©,64,32,16,8,4,0,0, 

3 • 24,8,8/8,8.24,0.0, 

t m 16.56,84, 16, 16. 16,0,0, 

_ m 0,0.0.0,0,0,0,252. 

£ m 24 .3t>. 32. 112,32, Jk, 124,0^ 

M -^ 0.56,4 , G0.C-O. 60 ,O.0, 

b = 64, 12©, od,6t5,68, 1^0 .0^0^ 

C «■ 0,60. 64, 64, 64, 6©, 0^0/ 

d « 4, 60,68, 68, 68, 6©, 0,0, 

« o 0,56,68. 120,64,56,© .0. 

( » 24,36,32,120,32.32.0,0, 

g = ©,56.68,68,66,60 .4, 56i 

h - 64,120.68,68.68.^8,0,0^ 

i » 16,0,43,16,16,56,0.©* 

J = 16,0.4 8,16.16,16.80.32, 

X • 64,64,72, 112,72 .60,©,©. 

t ■ 64^64,64, 64, 68 e&&<0>O/ 

m m 0,*0>e4^e4,64,84,0,0, 

n • 0,120,68^68,68,68,0,0, 

O « 0,56^68,68.68.56,0,0, _^ 

p « 0,120,68,66.68,120,64,64, 

q ^ 0,60.68,68.68.60.4,4, 

r « 0,56.68.64.64.64,0,0, 

5 « 0,56,64,56.4,120.0,©/ 

*. « 32.120.32,32.36.24,0,0, 

\. » 0,60,60,68.68,60,0..©, 

' tt 0,68.60,68,40,16,0,0, 

tf •-= 0,84,84,84.84,40,0,0, 

X * 0,68,40.16,40,68,0,0, 

y ■ 0,68,68,68, 68, < 60. 4. 56/ 

X - 0,124,8,16,32,124,0,0, 

-C « 48,32.32,64,32,32,46/0, 

J = 16,16/16,16,16,16,0,0, 

> = 24,8.6,4.8,8,24,0. 

- « 0.0,52,88,0,0,0,0. 

© = li2,136,232>200.232,136,lia. 



mode is selected, .all typing on the Spectrum 
will use the new characters^ the program 
listing may be shown in the new characters^ 
but instructions and menus will still use the 
Spectrum set. 

Redefine: any character in the new set can 
be redefined with this option. The Spectrum 
will require the character to be redefined and 
the decimal number of lines 1-8 of the new 
character. A display will be given showing the 
Spectrum character selected with the new 
character beside it; above this will be a grid 
with lines 1 to 8 and columns a to f indicated. 
As each decimal number is entered the 
character will be shown magnified on this grid 
and the actual size character will alter its shape 
accordingly. 

The character grid is in two colours, yellow 
and green; the yellow area indicates six 
columns a to f, and any redefined character 
should stay within this area as it is only this 
part of the character that is plotted on the 
screen. 

With this routine the whole keyboard could 
be redefined to suit your needs. If you want to 
retain your redefined keyboard then the word 
processor program will need to be reSaved 
with the command Goto 9900. 

The Spectrum will either buzz if an 
(continued on page 88) 



YOUR COMPUTER. MARCH 1983 85 



ZX KEYBOARD FOR USE WITH 80/81 SPECTRUM 

Our new cased keyboard has 52 keys. 12 of these are used for the numeric pad. The numeric pad offers some useful features, you can cursor with 
one hand and it will be a boon for anyone who enters a lot of numeric data. The pad is a repeat of the I -9 keys plus it has a full stop and a shift key. The 
numer k: pad keys are coloured in red. the normal keyboard keys are grey, with the case being black which makes the whofe thing very attraaive. The 
case measures 15x9x2/2. The computer (either 80/81 or spectrum] fits neatty inside. You will have to remove the computer from its originaf case, it is 
then screwed to the base of the case. The case had all the bosses already fitted and the screw holes are marked. Also fitted inside the case is a mother 
board (81 model only) which allows I6K. 32K and 64K to be fitted \n the case. All the conneabns are at the rear of the case re. Power, Mic, Ear, TV. 
and the expansion port. The case is large enough for other add ons also 
to be fitted msfde. One of these could be the power supply, then you 
could very quick^ fit a mams switch, or a switch on the 9V line. This 
means you have a very smart self-contained unit. Thfs case does not 
stpp you from usirxj ar^y other addons that you may have e.g Pnnter 
etc. We are convinced that this is the best keyboard available at 
present. It offers more keys and features than any other 'kcytx}ard m its 
price range. 



NOTE 

The case can be purchased separately with the keyboard aperture 
uncut, so if yo\; have one of our early uncased keyboards, or m fact any 
other suppliers' keyboards, these couJd be fitted. The keyboard is 
connected to your computer by a ribbon cable and this has connectors 
fitted which simply push into the Sinclair connectors, (t is a simple two 
minute job and requires no electrons skills. This keyboard does not 
need any soldering. Please specify on order whether you require the ZX 
81 or Spectrum case. 



SPECTRUM MODEL 

This IS supplied with spectrum legends, and a slightly different base 
for fitting the spectrum mside, again all the connectors are at the rear of 
the case and there is plenty of room for the power supply (and other 
addons). Should you want to change, we can supply both the 
Spectrum legends an6 details of updating your case which will enable 
modification from the ZX 81 to spectrum. PLEASEspecify on your order 
whether you require the ZX 8! or spectrum case. 




KEYBOARD 
(SPECTRUM/81) 



_ »L.%!hL t^_«v_ >' 




D 



El 



^•L 



1 1 lllllllll 



MOi»«nih^A«iC] 



Internal fixing for 
ZX 81 keyboard case. 



J-)-^ III 




Internal fixing for 
spectrum iteybbard 
case. 



SPECTRUM I UGHT PEN 



The pen enables 
you to produce high 
resolution drawings 
on your own televi- 
sion set, saving a vast 
amount of time over 
using basK: program- 
ming statements, such 
as Plot. Draw etc. You 
can erase, modify and 
save drawings and it 
comes complete with 
software program. 
The superb light pen is 
available from D.K. 
tronics. 




£19.95 



SPECTRI 

16K Memory Exp* 

The 16K uses 4116 C 
Static Ram and occt 
using the Static Rarr 
speed low power R^ 
the computer. All t 
which comes to yot 
where. Position in r 

64K Memory Expj 

All the above inforn 
advantage lies in the 
56K of usable memc 
the use of other adc 
8 1 92-65536. The BIc 
Spectrum Memory 
Upgrade your Spectf 
it IS simply slipped ini 
are supplied, and thi 
time. The fitting reqt 
same as Sinclair's up 



86 YOUR COMPUTER. MARCH 1983 



"81 Spectrum 

HARDWARE 




SPECrRUM/81 TOOLKIT 

This 15 the toolkit which won acclaim in the feature in the August 
1982 issue (pages 29 and 30) of 5^nclair User. "It is the most impressive 
program, fast in execution with clear and full fnstruaions...it stands out 
from the rest of the field. " The ZXED is a powerful editor for use on the 
expanded 2X81 . It is intended for use by the serious BASIC programmer 
and offers several useful and time saving features most helpful durir>g all 
stages of program development. The facilities provided are as follows: 
ALTER BYTES, COPY. DELETE. FIND. HELP, INSERT. KEEP, MOVE, 
RENUIVIBER AND VERIFY. The Soectrum Toolkit contains most of the 
features abov^ plus autoline numberer and append, and will run in the 

I6K and 48K spectrum. 




Both at 
only £6.95 



FLEXIBLE 

RIBBON 

CONNECTOR 

if you have ever had whiteouts 
or system crashes this coutd be 
the answer. It stops the move- 
ment between the computer and 
the RAM expansion, it is supplied 
with a ribbon, 6 inches tong, with 
a male conneaor at one end and 
a female at the other, at only 




UM MEMORY 



lansion £22,95 

Dynamic Ram Ch*ps. We use the dynamic as they are much denser than 
jpy less space. They are also much cheaper than the equivalent product 
T). The Ram is manufactured with high quality materials, and uses high 
3ms Jt is supplied ready-built and only needs to be plugged into the rear of 
the components are fitted into holders. This massive add-on memory 
)u fully assembled an6 tested is the cheapest 1 6K memory available any- 
memory from 16384 to 32768. (Same as the Sinclair memory.) 

T6K (UNCASED) £T9.95 
lansion £52.95 

mat/on on the I6K also applies to the 64K Memory Expansion, but the 
le 64K giving nearly FOUR times the memory. This advanced model has 
ory. In addition, the block from 8K to 16K can be switched out to enable 
d-ons. The graphics ROM is to be used in this area. Position in Memory: 
ock From 8 1 92* 1 6384 is swicchable. 64K fUNC ASEDJ £49.95 

y Expansion £35.00 

trum to 48K of user Ram. The Spectrum memory expansion is simple to fit, 
iSJde the case, and then only requires plugging in. Full fitting instruaions 
le only tool you will need is a screwdriver and just two minutes of your 
fuires no electronic skills. Position in memory from 32768 to 65536. (The 
pgradeto48Kl. ^^ 



4K GRAPHICS ROM £24.95 

The DK Graphic module is our latest ZX 81 accessory. This module 
unlike most other accessories fits neatly /nsideyour computer under the 
keyboard. The module comes ready buift, fully tested arxJ complete 
with a 4K graphic ROM. This will give you an unbelievable 448 exira 
pre-programmed graphics, your normal graphic set contains only 64. 
This means that you now have 512 graphkrs and with their inverse 
1024. This now turns the 81 into a very powerftjl computer with a 
graphic set rarely found on larger more expensive machines In the 
ROM are tower case letters, txtfnbs, bullets, rockets, tanks, a complete 
set of invaders graphics and that onfy accounts for about 50 of them. 
there are still atK>ut 400 left {that may give you an idea as to the scope of 
the new ROM). However, the module does not finish there, it also has a 
spare holder on the board whfch wfl accept a further 4K of ROM/RAM. 
This holder can be fiaed with a 1K/2K/RAM and can be used for user 
definable graphics so you can create your own custom character sets, 

WHYVWUT? 

ORDER TODAY FOR FAST DEUVERY 



16/64 MEMORY 
FORZX81 




The above illustration shows the casing for the I6K or massive 64K. 



I PleA\ffU«e type of m*cJ^rif,whKhRcKnfnerTK)fysj/e, quantity and place whe^ I 

Please send me @ £ 



Please send me , @ £ , 



Please send me - . @ £ 

Please add on £ 1 .25 for PIP 

In enclose cheque/P,0. payable to DK Tronics total £-.,..,. 

or debit my Access/Barclaycard | | [ | | j [ | | [ | j | | 



Stgnxutt , 
N^me . . . 
Address . * 



Send to DK Tronics. 23 Sussex Road. Gorleston. Gt. Yarmouth, Norfolk. 



Tel: Gt. Yarmouth (0493) 602453 



difh^mics 



I New colour bf oc hur c now d v^Mabk. send S A£ f of qukk return J 



YOUR COMPUTER. MARCH 1983 87 



1 continued from page 85} 
incorrect option is chosen^ or repeat the 
prompt, or skip the routine being called. A 
squeak will sound each time a menu option is 
chosen and valid entry made. In the 
Typewriter mode a key lap will sound with 
each key press. 

To load the program Enter the Basic 
program and Save it by Goto 9900; this will 
auto-run the program when complete. Stop 
the tape at the second Start tape prompt and 
Verify the Basic before Kewing it. 

Enter your favourite machine-code loader, 
Clear 29665 and enter the machine code. Save 
this immediately after the Basic program using 

SAVE "spc."CODE 29666,3102 
and Verify. 

Rewind to the start of the Basic program and 
Load "type'*. This will then load the Basic, 
the machine code and auto-run. The first thing 



to appear on the screen will be the main menu. 

If any section of the program fails to run 
then, using the list of routines and addresses, 
you should be able to check the machine code. 
I have purposely kept some of the program in 
Basic so that you may follow it more easily. It 
would be a simple task to convert all of option 
1 and option 6 to machine code. 

The routine starting at 29666 shows how to 
clear the Input lines 23 and 24 and which 
channel to open so that priming can be 
displayed on these lines. The Basic input 
InkcyS can be replaced by a call lo the ROM 
routine to clear the input lines, and the Basic 

PRINT #x; 

can be replaced by Open Channel and Print 
String ROM calls. The rest of option 1 is then 
a straightforward case of checking which keys 
are being pressed by Peeking the variable Last 
Key at address 23560 and making the 



necessary jumps, and calls. For example, line 
230: 

LD A, (23560) 
CP "n" 
JR NZ,NEXT 
CALL 31038 
JR LINE 50 
NEXT CP "m" 
RETZ 
JR LINE 60 

The only time a Ret to Basic would be made is 

when the Menu option is chosen, so line 1000 

would become; 

1000 RANDOMIZE USR 'START ADDRESS' : 

GOTOm 

and lines 50 to 780 and 8000 to 8040 could 

then be deleted. This would also have the 

benefit of making the Break key inoperable in 

the typewriter mode which can be annoying if 

Caps Shift and Space are pressed by mistake. 



The machme-code dump. 



29678 
2967© 

296S0 
29696 
S9702 
£97ea 
297i4 
2972© 
29786 
S973e 
297t>Q 
297** 
S975e 
S3T56 
S976a 
a9768 
e9'774- 
a973& 
S97e6 
£9792 
S9799 
29304. 
39810 
£9©16 

a9d2£ 
a9esd 

S9e34 

a9e4.0 

£9846 
a935S 
S9S5a 
£936* 
2967e 

a967e 

£9eee 
a9e94 

29900 
S9906 
&991& 
89916 
29924 
£9930 
29936 
29943 
e:9'£f4a 
299tS4 
29960 
29966 
29972 
S9976 
39964 
29990 
09996 
^0002 
^OC08 
30014 
30020 
30026 
30032 
30036 
3004* 
300S0 
30066 
30062 
3006© 
30O74 
30080 
30066 
30092 
30096 
30104 
30110 
30116 
30122 
30128 
30134 
30140 
30146 
30152 
301S3 
30164 
30170 
30176 
30162 
30X68 
30194 
30200 
30206 
30212 
O0216 
30224 
ar0230 
30236 
30242 
30246 
3025* 
30260 
30266 
30272 



42 


134 


92 


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155 


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197 


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122 


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175 


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243 


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32 


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13 


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66 


69 


67 


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111 


46 


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I 


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62 


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3B 





la 


232 


123 


16 





22 





10 


48 


16 


6 


143 


143 


143 


143 


143 


14 3 


16 


5 


143 


143 


205 


107 


121 


62 


2 


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1 


22 


6 


a 


197 


58 


233 


117 


60 


50 


233 


117 


36 


235 


117 


60 


50 


23S 


117 


17 


230 


117 


1 


16 





205 


60 


32 


193 


16 


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50 


233 


117 


62 


46 


50 


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117 


24 


101 


16 





22 


11 


11 


78 


69 


07 


32 


120 


56 


22 


9 


11 


97 


98 


99 


100 


101 


102 


22 


15 


1 


83 


60 


69 


67 


64 


82 


as 



30276 


7^7 


32 


6V 


"?2 


82 


46 


3028* 


32 


63 


32 


61 


32 


32 


30290 


32 


39 


7© 


6*5 


©7 


39 


30296 


32 


77 


79 


6© 


69 


22 


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1 


20 


97 


61 


49 


50 


30306 


56 


22 


2 


20 


96 


ei 


3031* 


32 


54 


52 


22 


3 


20 


30320 


99 


61 


32 


51 


50 


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r-032e 


4 


20 


10O 


61 


32 


4 9 


30332 


54 


22 


S 


20 


101 


ti 


30336 


32 


32 


56 


22 


6 


20 


30344 


102 


61 


32 


32 


S2 


62 


30350 


2 


205 


1 


22 


17 


40 


30356 


116 


1 


101 





205 


60 


30362 


32 


201 


22 


11 


© 


©0 


30368 


6S 


71 


69 


32 


©2 


69 


30374 


©1 


©5 


73 


82 


69 


66 


30380 


32 


63 


62 


2 


205 


1 


30386 


22 




156 


lie 


1 


18 


30392 




205 


60 


32 


205 


101 


30398 


120 


201 


22 


11 


O 


67 


30404 


79 


7© 


©4 


73 


7© 


85 


30410 


69 


32 


53 


32 


119 


105 


30416 


108 


108 


32 


114 


101 


115 


30422 


116 


97 


114 


116 


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77 


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57 


56 


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32126 








124 


16 


16 


16 


32132 


16 


16 








66 


68 


32136 


68 


66 


66 


56 








32144 


68 


66 


66 


66 


40 


16 


32150 








66 


68 


6* 


a* 


32156 


106 


40 








66 


*0 


"*.^1S2 


16 


16 


40 


68 








^;?i6tt 


66 


40 


16 


16 


16 


16 


32174^ 








124 


6 


16 


3a 


32160 


64 


12* 








46 


32 


32166 


32 


32 


32 


48 








32192 





64 


32 


16 


8 


* 


32196 








24 


a 


6 


6 


32204 





24 








16 


8© 


32210 


64 


16 


16 


16 








32216 




















u«2S22 





252 


24 


36 


32 


112 


U2<>20 


32 


32 


124 








56 


32234 


4 


60 


60 


60 








32240 


64 


120 


6© 


66 


6S 


120 


32a46 











60 


64 


6* 


32252 


64 


60 








4 


60 


322SS 


66 


66 


68 


60 








32264 





56 


68 


120 


64 


56 


32270 








24 


36 


32 


ia0 


32276 


32 


32 











56 


32262 


66 


66 


66 


60 


* 


36 


32266 


64 


120 


66 


66 


f->6 


66 


32294 








16 





46 


1© 


32300 


1© 


56 








16 





32306 


46 


16 


16 


16 


60 


32 


32312 


64 


64 


72 


112 


72 


©O 


32316 








64 


6* 


64 


6* 


32324 


66 


56 











*0 


32330 


64 


64 


84 


84 








32336 





120 


6© 


68 


68 


68 


32342 











56 


68 


66 


32346 


66 


56 











120 


i^GS* 


66 


66 


66 


120 


64 


64 


32360 





60 


66 


68 


66 


60 



32366 


4 


* 


1 


56 


68 


6* 


32372 


64 


6* 








56 


3237© 


©4 


56 


4 


120 








32384 


32 


120 


32 


32 


36 


24 


32390 











66 


68 


66 


32396 


68 


60 











68 


32402 


68 


66 


40 


16 





^ 


32403 





6* 


84 


64 


64 


40 


32414 











6© 


40 


16 


32420 


40 


68 











68 


32426 


68 


se 


68 


60 


4 


56 


32432 





12* 


8 


16 


38 


124 


32438 








40 


32 


38 


64 


32444 


32 


32 


46 





16 


16 


38*50 


16 


16 


16 


16 








32*56 


a 4 


8 





4 


8 


8 


33*62 


24 











52 


6© 


32466 













iia 


136 


324 74 


232 


200 


232 


136 


112 


O 


3a4SO 





56 


© 


92 


214 


4© 


32466 


195 


78 


121 





17 


1 


3249a 





33 


50 





205 


181 


32*96 


3 


201 


33 


14 





41 


32S04 


41 


41 


237 


91 


54 


92 


32510 


25 


6 


6 


14 


6 


66 


32516 


123 


61 


32 


a 


203 


34 


32522 


203 


34 


220 


22 


127 


^^ 


32528 


32 


248 


35 


16 


236 


201 


3S534 


197 


813 


j^ao 


33 


17 


22 


32540 


46 


175 


125 


7 


7 


133 


32t^46 


133 


111 


203 


36 


803 


36 


32552 


203 


36 


62 


175 


148 


103 


32556 


62 


6 


145 


133 


79 


120 1 


32564 


132 


71 


805 


229 


34 


225 




209 


193 


201 


33 


1 


60 


32576 


34 


54 


92 


201 


33 


224 


32362 


122 


34 


54 


92 


201 





32S86 














58 


1*5 


32594 


92 


203 


199 


50 


145 


92 


32600 


175 


56 


140 


127 


7 


7 


32606 


7 


71 


62 


183 


144 


71 


32612 


22 


6 


58 


139 


127 


tot ' 


32618 


79 


7 


7 


189 


129 


79 


3262* 


30 


6 


213 


197 


205 


229 


32630 


34 


193 


809 


la 


89 


32 ! 


32636 


845 


5 


21 


32 


229 


*2 




139 


127 


34 


26 


127 


3* 


32646 


23 


123 


201 


17 


22 


*2 


3263* 


139 


127 


24 


16 


205 


61 


32660 


122 


58 


245 


126 


119 


*& 


0*J66G 


139 


127 


44 


125 


254 


43 


3a^72 


32 


11 


46 


1 


36 


12* 


3267© 


254 


23 


32 


3 


33 


*3 


38684 


22 


34 


139 


127 


205 


23* 


32690 


126 


201 


1 


254 


25* 


237 


32696 


120 


254 


254 


192 


42 


139 


3S702 


127 


1 


254 


847 


237 


180 


32706 


254 


239 


32 


6 


45 


32 


3271* 


*6 


44 


32 


43 


1 


25* 


32720 


239 


237 


120 


254 


251 


38 


^52726 


13 


44 


125 


254 


44 


40 


32702 


4 


254 


43 


32 


84 


45 


32736 


24 


21 


254 


247 


32 


6 


32744 


37 


32 


14 


36 


32 


11 


32750 


254 


239 


38 


10 


36 


18* 


32756 


854 


23 


32 


1 


37 


34. 


32762 


139 


127 


205 


234 


ia& 


■ 



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MOTHERBOARD - SIX SLOTS £26.50 

MOTHERBOARD PCB ONLY £ 6.50 

SPECTRUM 28 WAY CONNECTOR £ 3.25 

MALE CONNECTOR £ 1.90 

34 WAY RIBBON CABLE permetre£ 1.80 

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40 KEY KEYBOARD £20.00 

SPARE KEYS each£ 0.25 

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DEPT. VC3 



REDDITCH ELECTRONICS 

21 FERNEY HILL AVENUE, 
REDDITCH WORCS B97 4RU 



YOUR COMPUTER, MARCH 1983 89 



MONnOR 



If you want to make the most of your BBC you will 

have to do battle with machine code. Richard Harris's 

monitor which tucks into just 2K of RAM yet includes a 

full disassembler should even up the odds. 



Why might you need a machine-code 
monitor? It could be that you want to 
investigate the machine-operating system, to 
see how programs and data are stored, or to 
test and change machine<ode programs. 
Perhaps you wish to investigate screen layout, 
or even to recover corrupted Basic programs. 
Whether you want to explore the workings 
of the BBC Micro or develop your own 
machine-code programs, this BBC monitor 
will fit most of the features of a good monitor 
imo less than 2K, including a disassembler 
which — since it is written in machine code ~ 
runs a lot faster than some of the BBC 
disassemblers available commercially. 

Six facilities 

The monitor offers six facilities. It allows 
you to: display and change the contents of 
memory; display a block of memory; move a 
block of memory; run a section of machine 
code; disassemble code; and set the values of 
6502 registers, run a subroutine and display 
the values of the registers on exit. 

The published listing contains the assembly 
program which assembles the machine code 
for the monitor. It is not necessary, of course, 
to type in the comments and the preceding 
backslash. 

Before running the program you must 
decide where you want the machine code to be 
assembled. Two of the most useful locations 
are below Page or above Himem. The version 
given here takes the first option and locates the 
monitor at 3600 — El in hex. To prevent it 



overwriting the assembly program, you need 
to move the start of the Basic program area. 
Once you have saved the program as listed, 
type in: 

PAGE -&1 500 
NEW 

LOAD "MONITOR" 
RUN 
You can now enter the monitor with 
CALL &E10 
If you prefer to store the 
monitor above Himem in Mode 
7, set P% in line 30 to &6000 
and type 

HIMEM = &5FFF 
LOAD "MONITOR" 
RUN 

CALL&6000 
After the assembly program has 
been run the machine code can be saved 
as follows: 

-SAVE "MONV E10 1500 or *SAVE "MONI" 
6000 6700 
and loaded with 

*'LOAD "MONT" 

Once in the monitor the screen should show 
0000 FF 255 ? 

hex hex and decimal prompt 

address values 

How to command 

The monitor accepts the following com- 
mands: pressing the space bar increases the 
current address by one, and Return decreases 
it by one. 

Entering two hex digits alters the value of 




the current 
address; and 

a full stop followed by four 
hexadecimal digits changes the current 
address. Entering the letter G displays an 
eight-by-eight block of data and addresses; 
entering R runs machine code from the 
current address; Z returns to Basic; and P 
enters the disassembler with the option of 
printer output. Press the space bar to continue 
disassembly and Return to leave it. 

M moves a block of machine code. It expects 
three addresses in the form of four hex digits 
each — the Start and End address of the block 
to be moved, and the Start of the new block. 



ie*?Ef1 MONITOR by R.W. 


Hirrlt 




20FORW-ITO2 






3et^r,»t£iz 




'Ren set bAs* Address or code 


4Bd*t A I -P>:*?55 ' d*t»2- 


P5:+lll0'dJit«3-P5i*1265 1 


50#fiesft-P?iH-142e rXYe^»s*P5S+l€35 - Pm^st^PH^ie?^ I 


e0dAtJi4«PJc+16T5 aRtab 


-P5;4i745 REM set bast^ iiddr^**** oT dAt* | 


70COPTe 






ee 


V 


of bi*te vAl^te#As used b¥ scr^rn^etc 


90 


V 


blTiATv is ActuAl b5#t« vAiue 


100 


\ 


»sb Is bits 4-7 isb is bits 0-3 


110 


\ 


n,K,Y,P refe'* to 6502 registers 


I20.»t«rt LDR *I0 






ISOSTfl «,8C'STR tei STft 


8.92 V 


ifiltlAllze vA^lAbles/ set current 


140LDR IHee'STfl 8.68 


N 


Address CCft> to 10000 


l50LDfi HIB'STR tSfl 






160LDR tHZ 






170JSR l-FFEE 


N 


cleAT screefi 


lee.rf JSR nm^Hn 


N 


reentrsi for *»ost routit^es/CR^LF 


l^.vS JSR total^rlnt 


\ 


Print Cfl JiTid vAtue In hey and declwAl 


200.* JSR 5.FFE0 


\ 


9et ftSCII vAWe of key Press , 


SlOCflP #t2E 






220BEQ «ddr 


\ 


if *.•* chAn^e Cfl 


230CI1P •32 






£408€0 nrKt 


V 


If "sPACe" increment Cfl 


2^0Cr?P tia 






2SQBEQ b*ck 


\ 


if "return" decreMent Cfl 


270Cftf> •45fl 






2806Nt 1 






290RTS 


N 


If "2- return to BASIC 


300.1 C«P •S-47 






310BNE in 






320 jr^ block 


S 


If "C* dls*>Uw block of hey values 


330. n Cnp #8.52 






340SHE T. 







350jriP < 8.0060) 


V 


If 


'•R" run machine code from Cfl 


360. n OIPHMD 








370BNE fl 








300jriP move 


\ 


if 


"M- wove block of data to new 9i<$<Sr9%* 


390. <»1 C«P #1,50 








400eKE q2 








410JMP diss 


S 


if 


"P" 9oto diss Assembler 


420. <l 2 cnp #8.53 








4300HE o 








440JMP subr 


\ 


if 


"S" 9oto subroutine set-yP 


450. o JSR Check 


s 


if 


won* of above > check heK key Press 


4S0CPK »0'BEQ A 


N 


if 


not 9et new keji Press 


4 70 JSR uPPer 


\ 


if 


hex convert to msb 


400JSR 9et 


V 


set 


r second hex ke^ Press 


490 JSR lower 


N 


convert to Isb/ combine with msb In ft [ 


500LDY »0 








510BTR <«-00>.Y 


\ 


chaT*9e value in CR | 


520Jf1P v/6 


\ 


to 


reentry 1 


530.Addr 


N 


routine to chAn^e Cfl | 


540LDy #2 








550, A* JSR kesisin 


\ 


9et 


, and display 2 key Presses for hi9h 


5603TR V007F,Y 


N 


b«t 


e^and 2 for low and store as Cfl 


570DEY 








500BNE aA 








590BEQ rr 








600. next 


s 


routine to Increment Cfl bv 1 1 


610INC 8.00 








620BHE er 








630IMC i.01 


V 


Inc 


:, hi«ti byte uhen low ^FF ^ t.00 


640jnp re 








650DEC t90 








660LDfl 8.90 








670CMP etFF 








6ee0NE ff 









90 YOUR COMPUTER. MARCH 1983 




After the first two 
addresses have been entered7 
the monitor prints a greatcr-than 
symbol as a prompt character. Entering S 
allows a subroutine^ starting at the current 
address, to be tested — so long as it ends in 
RTS. It requires the A,X and Y registers to be 
set and provides the option of setting the 
(continued on page 94) 



e^eoec ft© I 




\ 


d«c* hi9H bvt« wheii low ft©© ^ I.FF 


700JP1P rr 








718. 9»t 




V 


get* btK ktv Pr#»* 


r2eJ5R S.FFE0 








7OTJSR chtck 




V 


7 hex 


740CPX #8 








750BEQ 9*t 




V 


if not h#jc «et another 


7€V^S 




\ 


ir heK return^ value %j^ fl 


770. UP Per 




\ 


with "lower" convert* hex to biiiary 


rseCPIP •fc3fl 








790tCC cc 








eewec #7 




\ 


subtract 7 if «,R-«.F 


©10. cc SEC sec 


•ft 3© 


\ 


subtract 1-3© ©-9 and fcW-l.r 


eS^fiSL fl'flSL fl 


ftSL fl'flSL fl s 


rotate to H«b 


830STB ft92 




\ 


aM save 


©40RTS 








©9©. lower 








©eecfip *8.3R 








870ecc bb 








800SBC #7 








85©. bb SEC 5BC 


•8*3© 


\ 


convert hex to l*b 


^eacLC'RDC e.©2 




N 


add to fn*b* return with value In ft . 


91 ©UTS 








92©, block 




\ 


dls^Ui* ©X© block or hex 


93©L0ft t© 








9405Tfl 1.92 








95©LDY #© 








96©.CC» LDX •© 








9r0STX 1.93 








900 JSR ftew\ltv 








99©JSR *ddrPr 




s 


with address at start of each Une 


I©©©, be LOfl <I.©©>.Y 






101©JSR Prlttt 








1©2©LDV #2 









103© JSR sf>ace 






1©4©INC t-r© 


V 


inc. CR 


105©BNE ab 






1©6©INC 1.91 






1070, ab oec ft©3 






1©9©BKE be 






l©g©OEC t©2 






ne©©HE cd 






ni©j«p rr 






li2©.r%ove 


V 


routine to move block of data 


n3©L0Y #6 






n40JSR nei^lin 






1150. 9h JSR kewsln 


s 


9et 12 ke¥ Pr esses > at ore as start and 


U«©STR e.©©©2.v 


N 


eiw* a<kiresses of block, and start or 


1170OEy 


V 


new block 


ll©08eQ de 






1190CPY 114 






120©eN€ el- 






i2i0L£>ft •s.ac 






1220JSR tFFEE 


\ 


Pro«^t with -/" 


1230.»f CPY #2 






124eBN£ 9h 






125©LDfl tapSE 






126© JSR «.FFEE 


V 


Prompt with ->- I 


1270JMP ^h 


\ 


XXXX,YYYY>2222 dlsP laved 


1200.de JSR escape 


V 


OK to Proce*rf» 


129© INC «.©5 






1300BHE tv 






131©INC ^©6 


s 


inc. end of block # els* last bvte p«tlssed 


132©,tv LDR %.©3'STfi *,©© 






i330LDn 1.84 -STfl tSl 


V 


start of net.i block • new OR 


I340DEX 


N 


X- 1 on exit of JSR escape 


13W,td LDfl <a©7,X> 


V 


do move 


1360STR <t©3.X> 






13701NC 1.83 






1300BNE kw 






139© IMC I.84 






140©. km INC 107 






141©eNE hi 






1420IHC 188 






1430. hi lX>n S.37 






144 ©CMP €.8? 






14W8NE td 






!4e0LOfl ae© 






147CCf1P 8-e€ 






1480&NE td 






t490jnp rr 






I?©©.addr^r 




V Print Cft in hex 


!5ieL[>fl i8i 






1528JSR Print 






153©LDR t8© 






154© JSP Print 




1 


1W0LOY #3 




% 


1560 JSR space 'RTS 




V ♦ 2 %Paces 


1970.ch#ck 




V ? is 'value In ft hex 


1590LDX #0 






1790CMP #^3© 






1600©CC e 






16I0CMP ^%7f^ 




N lY RSCn 0-9 


l620eCC f 






1630CMP *»(,41 






1640BCC e 






l65©Cf1P »t47 




\ le «SCn ft-F 


I660BCS e 






1670. r LDX #1 




N if *e«, K- li if no. X- © 


168e.e RTS 






1690. total Print 




N Prints - 


ITeetDfi il3 






1 7 10 JSR tFFEE 




N CR 


1720JSR addi-Pr 




s C« 


1730LDft C$.80>.Y 






1 74© JSR Print 




V Hex value in Cft 


1750LDY e4 






176©J^R sPace 




\ 4 spaces 


1770LDR <C8.90>/Y 






178© JSR <imfi 




\ decinal value in CR 


1790L[>Y i4 






180© JSR »P«ce 






1010LDR di-SF 






192© JSR I.FFEE 




V "T- Profi^t 


1930RTS 






184©. Print 




N Print bintrir value In ft a* btx 


l©5©TftX 




\ save value in X 


1960AND lie.F0 




N mask Msb 


I870LSR ft'LSR ft 'LSI? fl^LSR flv rotate to Isb I 


188© JSR ProMt 




N Print 


189©TKft 




^ restore value 


l9©0ftND WF 




N p»«sk Isb 


1910 JSR Prout 




V Print 


1920RTS 






1930,Prout 




X converts binan* in ft 


1940CnP •!.« 






1950PCC ? 






1960CLC'flDC K7 






1970.2 ADC 1113© 




N to hex 


1980 JSR tFFEE 




\ and prints 


1990RTS 






2©0©.*P*ce 




N Prints spaces 


201 ©LDR t32 






202©, X JSR S.FFEE 






2©30I>EY 




V nuftber In Y on entrv 


2©409NE y 






207eRTS 






2060. dec 




N Prints binary in ft as deciinal 


2070LDX naSTX *.©C 




V na« for ■©" or leading blank Prints* 


2080. Vy LDY »l.3© 






2©93.kji CfV' a,89^X 




N count nu«b#r of I©©'* and 10' t i 


y 2ie©ecc kx 






2I10INY 






2120S©C 1.89, X 




N 100 or 10 subtracted tf^m ft/ count In ¥ 


2130BCS kv 






2140. kz CPY •i.a© 






2150BNe kw 






2160CPX •.©C 




V Print -e- or blank 


2170BNE kw 




N if none 


2ie0tDY #32 






2190DCC «,8C 






2200. kw PHR 




V else save rei*iindtP 


2210TYR 






2220JSR IFFEE 




V and Print count 

(//sting continued on page 93} 



V 



YOUR COMPUTER, MARCH 1983 91 



NEW SPECTRUM AND 
ZX81 SOFTWARE 

"WINGED AVENGER ' 

FmI «nd runous SPECTRUM veiMon has SOUND and USER GRAPMfCS 7 LEVELS. 
3 WAVES. MOTHER SH*P, HKiH SCORE, RE-FUELLING. RAPID fiPE, SMART 
BOMBS *nd LASER SHIELD, PCW 'OHB OF THE BEST SINCLAJR GAMES YEF. 
Onl/£4,50 All SPECTRUM + 16K ZXS\ 

"SPECTRUM SCRAMBLE" 

MORE M/COOE ARCADE ACTION "SO GOOD THE REVIEWERS DIDN T REACH* 
THE FINAL STAGE' (NOT BAD EHH). NO LESS THAN 8 DIRECTIONAL KEYS tor a 
SMOOTH MOVE Full ARCADE features incJudif>g. LASERS. BOMBS. INSTANT 
RESPONSE. CONTINUOUS SCORING. ROCKETS. SOUND, FUEL DUMPS, RED 
HAETEORS, DEFENDER CRAFT and HK3H SCORE. Bewara CONDITK>N RED With 
ilwa one you MOVE. FIRE and BOMB AT THE SAME TIME. RELEASE PRICE ot 
t4M IGK Of 4$K SPECTRUM. 

"DO NOT PASS QO" 
NOW THE 4eK SPECTRUM VERSfON IS READY 

A COMPLETE SIMULATION of the BEST SELLING BOARD GAME. yOu know PARK 
LANE arid an irvat up to S»X PLAYERS CAn comptie wrtn tne MICRO dotng an iha 
WORK. Acts as DICE THROWER. BOARD. RENT COLLECTOR. UMPIRE. BANK. 
RULE BOOK. ACCOUNTANT nod PROPERTY RECORD. SUPER GRAPHICS Oy 
Gary Kennedy (tnanks male) GAME SAVE wrth winner 50 t&t report COMPLETE wtth 
INSTRUCTK>N BOOKLET The ULTIMATE in FAMILY GAMES Don't MONOPOLISE 
YOUR M(CRO AMAZE all your tnends ^nc family (Can you see yoor GRANNY on a 
MICRO?) ONLY C6-&5. 16K 2X8 1 VERSION ALSO e6.9S. 

*BASE INVADERS" 

The ONLY ARCADE OAmE EVtHfoUuY SHOULD HAVE TTie SCREENS the 
same. THE INVADERS are the same. BUT you get a SHIELD and a CHOICE of 
THREE SPEEDS. (O.K.. FAST or INCREDIBtEl. GOOD SOUND, a HARD GAME, 
and GREAT GRAPHICS. COMPLETE your software ojllection for just C4.50. 16K and 
4aK SPECTRUM onfy. 

'•AUDIO SONICS" 

WINNER of WIZ2 KID 82, For If^e SPECTRUM AS wrrtea soufXJ effects tor your own 
programs 26 PRESELECTED SOUND EFFECTS incitide TELEPHONE. POlK^E 
SIREN. FROG, SPACE EFFECTS and OUTBOARD MOTOR GO into MODIFY and 
you are presented wrtfi a display of SLIDER CONTROLS to adjust PITCH. RISE. FALL. 
BRtSKNESS. DECEL. ACCELL. TONE. REPEAT RATE. STUTTER and DELAY. 
ADJUST iho SLIDERS then INSTANTLY tiear the SOUND CREATED. Call "THE 
SOUND ONE' arK] a program tioe wiM appear tfiai is ready for maertton into yoi»r own 
programs Hours of EXPlORATK>N, YOU WILL BE AMAZED what BEEP can DO. We 
are proud lo offer this at UW leK or 4aK SPECTRUM. 

"SPECTRUM RENUMBER DELETE" 

All MCODE RENUMBERS ALL NOT PART "YOU WONT BUY A BETTER* 
RENUMBER PROGRAM FOR THE SPECTRUM ' JUST 800 BYTES At £4.96. ALSO 
2X8t VERStON 

'HiQH NOON" 
When YOU VE SAVED the GALAXY. SCRAMBLED or whatever else you do on your 
MICRO, what about a GUNFtGHT-* Play the SPECTRUM of YOUR PALS. THREE 
LEVELS. FULL FEATURES. CACTI. COFFINS. WAGONS. RAPID Of SINGLE 
SHOTS SUPERB GRAPHICS. GOOD SOUND »nclud*r>g DEATH MARCH. ESCAP- 
ISM on TAPE for JUST £4.50. 

"DISPLAY" 
Takes over when BIN and the DEMO tape left oft How would yoo l«ke 27a different user 
dettned GRAPHICS on a 16K SPECTRUM or a GRAND 336 tor a 4eK. Ai( of these can 
tw displayed on the screen at the SAME TfME. UDGs are stored as PAGES and any 
TWO PAGES may be exchar>ged in memory FILES can be LOADED FROM or 
SAVED TO TAPE. LOAD into any pa^e location. TURN a UEXi % turn. »^ turn. FLIP a 
SHAPE Over. REVERSE a SHAPE. EXPAND V* oi a CHARACTER mto a fui 
chafftcter. UP. DOWN, LEFT or RIGHT by cme PIXEL. 5 SHAPE FILES are incliKJod on 
TAPE. INCLUDING a 64 CHARACTERS per LINE DISPLAY. COMPLETE with DEMO 
PROGRAM and INSTRUCTIONS. JUST RELEASED at £7.00. 4eK or 16K SPEC- 
TRUM Of>ly 

■TRaceON" 

BASED on a FILM (GUESS WHfCH) TRaceON is a REAL TIME ADVENTURE for 
thc^e of you who cant handle ARCADE GAMES Your TASK ts to COMPLETE a 
TRILOGY of GAMES Successfully A poor PERFORMANCE Wfcl resuft in a RESTART 
as may CHEATING MASTER ihe DISKS and YOU 9et to n6tt a LIGHT BlKE and then 
RUN the CORRIDORS ot DEATH to reach tne MASTER CONTROL. REALLY GOOD 
FRUSTRATING FUN. 4aK SPECTRUM £4.S0 (16K coming soon. J 

"MATCALC" 

Foe BUSINESS and PROFESSIONAL use Ideal for WHAT IF situations. CASH FLOW 
FOREC STS orKJ analysing RELATED figures 64 character display option FORMU* 
LA ntay be MATHEMATICAL or LOGfCAl MENU of FUNCTIONS SAVE and LOAD 
DATA lo TAPE FULL insiructKKis irKfuded LfTERALLY HUNDREDS of USES BOTH 
48K and 16K SPECTRUM PROGRAMS on ONE TAPE JUST C7.00. EXCELLENT 
VALyE 

''PROGRAMMERS DREAM" 

A SPECTRUM TOOLKIT. Posiuon indeperxSent and just 1450 BYTES. Facilflies 
RENUMBER lines or blocks any increment or start BLOCK OR LINE MOVE including ' 
a RENUMBER inio place it required BLOCK OR LINE ERASE. CHANGE SELECTED 
STRINGS r NAMES OR CONTENTS) DUMP var^tle names and values (usable tn « 
loop) DISPLAY PROGRAM or PROGRAM pfus VARIABLE SIZE INSTANT and 
CLEAN JUST £6 9S with exploit insUuctiOns. 

WORK FORCE 

140 WILSDEN AVENUE, LUTON, BEDS, ENGLAND 

ALSO AVAtlABLE AT BUFFER. MICROWARE AND SOFTWARE SUPERMARKET. 
REM WORK FORCE WORKS HARDER. 



C J F 13(30 

fcJ» mmMm Wkmm SPECIALISTS 

microcamputers 

VAT induded where applicable 

QUALITY DISK DRIVES 

Single drive 40 tiack single sided 1 x lOOk £200.00 

Dual dnve 40 track single $ided2 x 100k €350.00 

Dual drive 40 track doubte sided 2 x 200k €546.26 

Dual drive 80 track doub^ sided 2 x 400k €799,25 

All drives are cased with own PSU for reliabiUtv, 

arid tnctuda connectir^g cabies and utilities disk. 

Delivery €4.00. 

SOFTWARE FOR THE BBC MICRO 

MISSILE CONTROL the first implementanon on the 

BBC Micro of the popular arcade game. (32K} £9.00 

MAZE MAN an authentic version of the popular 

arcade ganrw. (SSKJ €6.00 

BALLOONS a highly original game that soon becomes 

compulsive playing. (32K). €6.00 

DISSASSEMBLER the menrwry dump routine inckides 

a scfoWng back in memory facility. HSKJ , . €5.00 

MISSILE CONTROL, MAZE MAN & BALLOONS 
use the Keyboarc or Joysticks for control 

30+ PROGRAMS FOR 
THE BBC MICROCOMPUTER 

This Book contains program listings, with explariations €f 

tips on using the BBC Micro 

GAMES UTILITIES GRAPHICS H MUSIC 

Most programs wll run on Model's A Er B 

Edited by C.J. Evans, vark>us Authors. 

A pair of cassettes with all the programs is available. 

BOOK £5.00 
BOK b CASSETTE SET £9.00 



LEADS 

The BBC Micro comes without a cas&ette lead 

7Pin Din to 2 X 3.5mm £r 1 x 2,5mm minijacks , ...,., C4.00 

7Pin Din toSPin Din & 2.5mm minifack £4.00 

7Pin Din to 7Pin Din ... . C4.00 

7Ptn Din PLUGS Two for £0.66 

6Ptn Oin PLUGS (for RGB socket) Two for £0,65 

5Pin Otn PLUGS (360' for RS232). Twofof £0.66 

RS423 TO RS423 IBBC Micro to BBC Micro) 
Two metre cable €4.00 Four metre cabJe £5.00 



TELEVISION/MONITOR LEADS 
full range available 

Phono pEug to Coax with high quality cable 3 Metres. ...... £3.00 

BNC Plug to BNC Plu^ £3. 10 

BNC Plug to Phono Plug 
(i.o. B8C Micro to Rediffuston TVRM) . £2,20 

PRINTER CABLES 

BBC to 36 way Centronics Type connector £T7.50- 

BBC to 25 way Type (Fof use with RS232) £9.50 

BBC to 40 way edge connector (Centronics 739) £20.00 

TORCH to 36 way Centronics Type connector. £20.00 



BLANK C30 COMPUTER CASSEHES 

Ten for £4.50 

15 Way Type Plug with Cover £2.75 
Computer graphics design pads 100 sheets £4.00 



BBC UPGRADE KITS 

RAM UPGRADE (lOOns). £23.00 

KIT A Printer & I/O Port £9.50 

KIT 8 Analogue Port .£8.00 

KIT C Sefiai I/O & RGB , £10.00 

KIT D Expansion Bus/Tube .£7.50 

Full Upgrade kit .,...,... £58.00 

All components fuH specification 



STAR DP8480 PRINTER 
FROM £250.00 INC VAT 

80CPS : 80 '96/ 132 COLS 

BIDIRECTINAL LOGIC SEEKING 

TRACTOR WITH FRICTIOM FEED 

CENTRONICS. £717.39 4 £32.61 VAT - £250.00 

RS232 £235,00* £35.25 VAT = £270.25 

High Ros Graphics option to allow BBC Screen dumps 

£15.00/£20.00 
(24HR SECURICOR DELIVERY FOR PRINTERS £8.001 



VAT included where applicable 

Send SAE for full Price List of our large rang^ of accessofies- 
POSTAGE Add 50p per order or as stated 



C.J.E. 



2PA 109062) 6647 



92 YOUR COMPUTeR. MARCH 1983 



(listing continued from page 91} 

3230PLR ^ rr»tor« r«m«lT>d«r 

2240D€X 

2250BNE Vx 

227CJSR I.PPEE 

2300LDn r^»»»-l,Y 
2310JSR tFFEE 

2340RTS 

235©.YorN 

2360JSR SrFFEe 

237©Crtf» IWr59 

238ee€Q ^3 

239«CW> •t.4E 

24009ME Yc»rN 

2410LOX ia^RTS 

2420. "13 LDK »1'RTS 

2430 , t>#wl 1 n 

2440 JSR i.rFE7JSR S.FrE7*!?TS 

24"!0.k«^»in 

2460JSR 9*t 

247ej5R 8.FFEE 

24eeJS^ uPPer 

2490JSR «et 

2^00JS« I.FFEE 

2^10JSR l6w«r 

2520PTS 

2530. dl»» 

2^40 JSR nrwltn 

2950tOY #181 

2iy€0LDX »13 

2570JSR n#««a9« 

2580JSR forH 

2590BEQ ^4 

260eLDY PI?© 

2«10LDK »7 

2€2?JSR we***0^ 

2€30.**4 LOR •1-14 

2€40STfl 483 

26^:0.45 JSff aFFE7 

#0 



V u^«n unit* \mt% convert to h#x awel ^rlf*t 



V Prints "mtmtt^*" 

V Y hold* start !n« ^ol«t In "MtftStt* d«t*" 
\ K hold* l^n^h 



seeetDY 

2€7eLPR Cte0>.Y 
2€80tDX #t?7 
gg9g.4g CMP d*ta3.K 
27©6BEQ 47 
27ieOEK 
2720eNE <I6 
2730JSR M^fi^ir^f^ 
2740tOR <«.e0>,Y 
27WJSR ^rlT^t 
276eLDY •10 
2770 JSR sP*ce 
27«0LaY tl^l 
27SeLI>M #10 
2O0OJ8ff m*%%m^^ 
2et0.l9 TI'C t8^ 
2e^BHE ^B 
2830 !WC 1.81 
2e4«.«»e DEC «r83 
28^0eNE ^5 
28€0.ul J?R tFFE0 
2870CW* #«.20 
288e8Ea 44 
2e90CMP #fc0D 
290^NE wl 
2910LOY #203 
2520LDX #3 
2930 JSP m»»*»^* 
2940JHP rr 
29S0.47 LDR d*tJ2,K 
2960STft 8.84 
2970LDR d*t*l.X 
29e©STR t85 
2^*»0TflX 

900«I.[>R datji4,K 
3e!0STR <.96 
3020 JSR *ddrl>r 
3030LDR (&00>-Y 
3040 JSR Pri^% 
?0T'0LDX 1.86 
3CC0PEQ u2 
3C70.W3 INC 1.80 
3080BKE u'4 
3090INC ftei 
3100. u4 LDR #32 
3n0JSR e.FFEE 

3i2eLDR ^tee>.v 

3I305TR &87.X 

3140$TX KB7 

3150JSR Print 

3l€0LOX 1,87 

3170DEX 

3ie0SNE w3 

3130LDX t8€ 

3200. w2 LDY «Ptab+i.X 

3210JSR *PJic# 

322eLDK 43 

323eLDY 8.84 

3240 JSff r%9s«««« 

3250LI>fl 1132 

32S0JSR B.FFEE 

3270LDY l,8S 

3280BEQ w^ 

32901 NY 

3300. w6 LDR d«t«4,Y 

33ie8EG w7 

3320CMP •! 

3330eEO w7 

3340CI1P tl-FE 

335e8NE ue 

33ggLD X B,eS 

3370BE0 w9 

330eJf1P 4f 

33f0.w9 JHP 40 

3400. u7 TRX 

3410tDR 8.00. X 

3420 JSR PrlT^t 



N 9»t* •lth»r -Y" <K#*> 
s or *N" Cfto> k»v Pr#*A 



N If no. X- 0. if y#* X* I 

\ do«* 2 CR^F 

N ^et* «nd di«Pl*4#» 2 h#K lc«» Pr#ftft»ft 



V coT\v#rt* to blT>«rv* In R on #xlt 
N dls**»»inbltr -»t«rt» *t CH 



s ? oatPut to Printer 



V if ^m% Inltlttlz* Printer 

^ v«lu** ^lv*n for MlcroHn^ 80 

\ counter for Un#s of out#ut 



N «#t value In OR 

V ch#cit If oPeod* 
\ tf 1*> branch 

s if net - 

V Print Cfl 

^ and cotitent* 

^ 10 %P9,C*% 

■^ NOT OPCODE message 

\ Increment Cfl 

V ref^eat tit I re4uiirecl iuii*ber of lines 

V ^t key Press 

V If "spfce" continue dlssasftenbttf 

V If "return** exit to monitor 

s turning off Printer 

\ if value is opcode. X Is Pointer to 
N «et Pointer to "name- In p»essa9e d*tA 

V «et Pointer to *• address tvPe* dut* 

N use tht* Pointer 

s to 9et nuinber of bytes from 

N *a^fi<ir%%% tifPe" data 

V Print CR 

^ *nd contents 

V restore "nup^er of bytes" 



N increment Cfl 

s ^rlnt sPace 

N get and PriTit and store value in new Cfl 

N repeat for number of bwtes 



N 9et namber of spaces from table 
V and Print to keep output aliened 



N print opcode njine 

V and sPace 

V address tvPe Pointer 

V branch if "relative" 

V Skip "no. of bi»tes" data 

V 9et byte from "address tyPe data" 



s br*nch if or 1 

N If •FE* return for newt oPcode 



V avoiding Inc. Cfl If was "relative" 

^ if data 8 or I then Print 

^ bl9H or low byte of address field 



3430 I HY 
34408NE u6 
3450. w8 JSR &FFEE 
3460 INY 
3470BNE m6 

3480* m5 LDfl tee 

3490TRX 
3500 INC &B0 
391 ©ONE el 
35201 NC f.81 
3530. el CLC 
3540ROC 1.80 
35585TR 1.89 
35€0tDY S.81 
3570TKR 

sseeepL e2 

359eGC5 e3 

36e0D€Y 

3610. e2 8CC e3 

3620 I NY 

3630, e 3 STY 8-88 

3640LDY «7 

3650eNE v6 

3660. a2 SIX ^85 

3670J3R keys in 

3680LDy ^65 

3690STR 8,85, X 

3700Drx 

37*eDEY 

37200NE al 

3730. subr 

3740 JSR newlln 

3750LDY #33 

3760LDX #3 

3770. a 1 LDR XY«e*s-l,Y 

3780BEO a2 

3790JSR 8.FFEE 

3ee0DEv 

?et!08^r a I 

3S20STY S.84 

3830 JSR YorH 

38408Ea a 3 

3B50JSR newlin 

386eLDY #4 

3©70STY t.84 

3^0. *4 LDR Pme-»-t-Y 

3890JSR ftFFEE 

390eDE^ 

3?108NE a4 

3?20J?R keys in 

3930STR B.89 

3940. a3 LDfl IW.4C 

3950STR 8-7F 

396ejSR escape 

3970JSR newlin 

39e0tDX t88 

3990LDY 1.87 

4000LDR fc86 

4010PHR 

4020LDR S.Q4 

4030SEQ a5 

4040LDR «.89 

405^MR 

4060PLP 

4070. *5 PLR 

4080 JSR 1007C 

4890STX 8-88 

4100STY i87 

4Ue5TR 8.86 

4120PMP 

4130PLP 

4140STfl t89 

4150LDY #33 

4160t,DX #3 

4I70.«6 LDfl 

41300EQ *7 

4 190 JSR tFFEE 

4200DEY 

4210CPY #15 

4220BNE a6 

4230LDY #3 

4240. ae LDfl Pmess-IY 

4250JS« e^FFEE 

42€0DEY 

4270W« J8 

4280LDR 189 

4290 JSR Print 

4300JMP ff 

4310. a7 LOfl 8'85#X 

4320STX 1*85 

4330 JSR Print 

4340LDX t85 

4350DEX 

4360DEY 

4370eNE aG 

43^0. TScaPe 

4390 JSR newim 

4400LDY •210'LDX #7 

44 10 JSR fnessa9e 

4 420 JSR YorN 

44308HE v4 

4440Puft'Pt-fl 

4450JMP ft 

44«0.v4 RT8 

44703^ NEXT M 

44«e 

4490 

4900 



V If not 0M.FE Print flSCIl e4ulv 

^ next byte of •'address tyPe data" 
\ relative branching sums 
\ branch value In X and R 



N Increment Cfl 

V add branch value to lov bwte Cfl 

V get high bvte In Y 

V restore branch value 
N T branch ♦ve or -ve 



'^ Inc. or dec. Y if over Page boundary 

V and store m% new high byte 

V return to Print out as if 
absolute addressing 

^ save X 

^ get and Print 2 key Presses 

s restore X 

V save binary value for Y^X/R 



V subroutine se-t'-uP 



V get data for nessage 

\ branch if C3 tli«^s> for Input 

N else Print ASCII e^ulv 



set flag to 

"yes or no" t^ set statu* request 



if yes 
Print 



reset 

P- 



flag 



get key P'^es* inPut 
save binary 

Put JMP opcode before 
OK to Proceed^ 



Cfl 



N set X.Y with stored values 

s save value for fl 

\ if flag set 

V get value for P 

N set P via stack 

N set fl without affecting status P 

N do sijbro'Jtlne at CR 



^ %M\?9 X^Y*R*P on return 



XYmess-i^r N Print i*iessage -branch if data • 



pr itYt "P*" message 



Print hex of P 
return to monitor 



^ get and print X,Y/fl in turn 



N OK to Proceed routine 



N Print message 

\ get yes or no response 

V if no return to monitor 

V correcting stack for 1 subroutine 

N If yes. Proceed 

REfl 

REM DATA STRTinEm'f 

REM data4« *' address t^Pe** dlta 

datal" Pointer t© data4 
REM data2« Pointer to message data 
REM data3" oPcodt %%trch table 



"♦CHR^COH" -fl '•♦CHR»<0>*" *Y 



4910 

4520 

4530»Pmess-*- -P " 

4540 

45500XYmes*'"''N>Y sutatS teS 

•*'K>IP«O<0>*'' *«• 
4560 
4570!^?Si* ■' f^^JRCD<*L?PKR8LP8I MeOE8EMBCVP9V8CCI>SC8T 1 ©YPCXPCPftCOLC r LCC 

LCVLCR0CY10»0lDCEDYN I CN I XN I <>M JR3 JADLKDLYDLRSLPONR«OflHPALPP>^PLP 

^ORLO^eTRITRCiS' 
458er^?5#-MES?fi+«KTSYT8flT5CE3IE5DE8XflTflKTYflTRYTX8T«KT TH/Y RETNIRP 

4590FORJ-1T012 ' READS Wsting Continued on next page) 



YOUR COMPUTER, MARCH 1983 93 



{continued from page 9JI 
status register. On return from the subroutine 
it displays the contents of the registers. This is 
very useful in exploring *FX and other 
operating system calls. 

The program listing is well annotated which 
should make it relatively easy to follow for 
those who want to understand exactly how it 
functions. One improvement they could try is 
to insert a routine into the disassembler to 
print out the ASCII characters for each 
bytes. 

To put the monitor through its paces, you 
might like to try the following procedures. 
Enter the monitor with Call &E10 and then 
change the current address to &E10 by 
pressing the full stop key and typing OEIO. 

Viewing versions 

Remember that the monitor only accepts 
four-figure hexadecimal entries. If you now 
press P you will see the same disassembled 
version of the monitor that you keyed in 
earlier. 

Press M and then enter OHIO, 1500 and 
4000. This will copy the monitor to &4000 
and if you press R it will call itself. 

Finally you could try the facility for testing a 
subroutine by calling OSASCI. This is the 
operating system routine which writes a 
character from the Accumulator to the screen. 

First change the current address to &FFE3 
and press S. Set the X and Y registers to zero 
and the A register to 72, the ASCII code in 
hex for lower-case R. When run OSASCI will 
print a'lower-case letter R to the screen in front 
of a display of the contents of the X register. 



(f is Ting continued from previous page) 

4eWt1E8S»«rTC5S»+CHR*< S > ■ NEKT 

4«1»WTW/ 3e. 1 . 66/ 1 . 27v 1 . 69. 1 . 27. 1 . 3 

46MfieBS»iinC5S»*"?H/'Y KO" 

463e«h#lft«nE3S« 

4640 

46^«rOH J>S* 1 T03 ' RERDSH 

466etr tub? J>5*iS>: ' HtXT 

467«)ffTni 0.7/4 

46M 

465«F0R JX-0TO68 ' REftDSH 

47Mdttli4?J>l-iS>: NEXT 

4710OflTRl.l.t23.l,26/0.6.FE,2.8*26.0/l/«*FE,2/l,26>0.1/l*2C.M9/^FE.2.8*26.0/l.e.2C/W9 
, I.FE/ 1 > 1*26. 0/ S,FE/ 1 . 1.26. e. S.2C/ 159 

4720DRTR|,FE . 1 . 8*26/0. «.2C. 459. IrFE. 1 . S.20. 126/ 0. M9. 8.2C . W9 . S-FE . 1 . «.2e. 1.26/ 0. 8,20. W8 
. «t25.tfE. 2/ «.28. 8.26. 0.1. 8,25/ 8.FE/0. 6.41. S.FE.0/8.FE 

4730 

4740FOR J5:- 1 TO 1 5 ! » REflDS?i 

4750d« t* ! T J9<*SX ' NEXT 

4760DRTR67.49.25/25/67. 1/64/6.6/0/41.29/29/67/ 18/ 11. 11.6.49,25.25.29.67. 1/64/6. 
6.6.0.41,29>29.67.10,ll.ll 

4770DflTR67,49,25/ 25.67. 1,64.6.6.6.0.41,29.29.67.10.11/11.67,49.25.25.67.1.64.57 
.6.6.0.41.29.29.67.10.11.11,49.25.25,25.67/67.6.6/6.0,41.29.29.35.67/18/67.11 

47e0DRTR1.49. 1.25.25.25.67. 1/67.6.6.6.0/41.29.29.35.67. 18.67. 11/ 11. 18. 1.49.25/2 
5.25^67. 1.67.6/6.6.0.41.29.29.67.18.11/ 11.1.49.25/25.25.67.1.67.6.6.6.0^41.29.29 
.67.18.11/11 

4790 

4800FORJH*lTrjl71 RERDSSC 

4810d«t a2?J5c-SH ■ NEXT 

4e20DnTR12. 105.105.9.114.105.9. 105.9.15/105.105.9.57.105.105.9.87.3.39.3.123.11 
7.3. 123. 39. 3. 123.18.3.3.123. 144.3.3 

4830ORTfll23. 129. 63. 63. 99. 108. 63. 99. 84. 63/ 99. 27. 63. 63. 99. 54. 63. 63. 99. 126/6/6/ 120 
.111.6.120.04.6. 120. 3R. 6. 6. 120. 147..6.6.120 

4a40DRTR141. 138. 141. 135.66. 156. 138. 141. 135,33. 141 . 138. 141. 135. 162. 141. 168. 141.9 
6.90.93.96.90.93.159.90. 153.96.98.93.36.90.96.90/93.60.90. 165.96.90.93 

4850DRTfl42. 48/ 42. 48. 72. 75. 48. 69. 42. 48/ 72. 24/ 48. 48. 72. 51. 48. 48/ 72. 45. 132/ 45. 132/ 
78.81.132.102.45/132.78.21.132.132.78/150.132/132/78 

4860 

4870FnRJ5i«lTO151 ' RERDSH 

4880df t A3? J5;-S?: ' NEXT 

4890DRTR0. 1.5/ 6. 8. 9. e-n. 8.0. 8»E/ 8*10. Icll. 8,15.8*16/ 8.18. 8.19. 8.10/ 8»1E/ 1*20. 8<21. 8.24. 8-25. «*2 
6. 8,28 . 8.29. 8.2R. 8t2C/ 8.2D.8.2E. 8.30. 1.31 .8.35/ 8.36. 8.38. t39. 8.3D.8.3E 

4900DRTR8*40. Ml. 8.45. ?,46/8i48. 8,49. I<4fl/8.4C.8.4D.8.4E. 8.50. 8^51/ 8.55/ 8.56. 8.58. 8*59. 8<5D.8r5E 
. 8*60. 8,61 . 8.65. 8.66. 8*69.1-69. 8.6R. I.6C.8.6D. 8.6E. 8.70. 8.71 . 8.75.8*76. 8*78/ 8.79.8.70/ 8*7E 

49 1 0DRTR8.8 1.8.84. 8-85 1 86. 8c88.8.8R.8.8C/ 8.0D.8.8E. 8^90. 8*9 1.8*94 .8.95. 8.96. <i.99. 8*99. 8r9fl. 8.90 
/ 8«R0. 8*R1 . 8.R2. 8.R4 . 8.R5. ^R6. 8.fl8 . S.R9. 8.RR. 8.RC. I.RO/ 8.RE 

4920DRTRt B0.8.B 1.8.04. 8.05. 8*86 188.8.89. 8.eR.8-BC.8.BD. 8.BE.8.C0.8.C1/ I.C4. 8*05/ 8.C6.8-C8.8.C9 
.&CR. 8.CC. e-CDi 8.CE/8.D0. 8.01 . 8.05. 8<D€. 8.D8.8.D9. 8<DD. 8.DE 

493ODRTRtE0 . feE 1 . 8*E4 , 8tE5 . S.E6 . ?.Ee . 8*E9 . 8,ER . 8.EC . 8.ED . 8.EE . 8«F0 . 8.F 1 . «*F5 . 8.F6 . 8<F8 . 8<F9 . 8.FD 
.t<FE ■ 




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94 YOUR COMPUTER, MARCH 1983 






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96 YOUR COMPUTER. MARCH 1983 



BBC 
ASSEMBLER 



You can always tell a good 
assembler by its range of pseudo- 
op codes. Chris Melville looks at 
the BBC's resident assennbler. 



In more advanced assemblers we expect to 
see a wide range of pseudo-ops that could be 
used in our programs at assembly time. Figure 
1 gives examples. 

One should remember that all pseudo-ops 
are merely instructions to the assembler and in 
no way afTcct the machine code produced 
when it is eventually run. 

The BBC assembler is part and parcel of the 
BBC Basic interpreter. As such it has access lo 
the expression evaluator used in BBC Basic 
which means that almost any sensible 
expression that is valid in BBC Basic, 
providing it has a numerical result can be used 
inside an assembly language program. This in 
turn means that a lot of the funcations and 
variables available in Basic can be used^ 
including your own as defined by Def Fn, as 
long as the results they produce arc 
compatible with where they are used. For 
example, all of the following would assemble 
as the same thing: 

LDA#SIN(RAD(90H*30 + 5 

LDA#35 

LDA#&23 

LDA#ASC"#" 

LDA#A% 

1^ has the ASCII value 35> A% has previously 

been assigned as 35 and ampersand indicates 

hexadecimal value in BBC Basic. 

Any expression resulting in a floating point 
result will merely be truncated to the next 
lowest integer. 

The Basic interpreter is suspended and the 
assembler brought in at any lime by using the 
Basic statement [. Similarly the assembler 
returns control immediately to the interpreter 
on encountering). Upon leaving the assembler^ 
executing some Basic and then returning 
again to assembler, all assembly pointers 
such as the location pointer remain 
unchanged. This facility allows Basic and 
assembly language to be freely mixed and we 
will shortly see that mixing the odd Basic 
statement with the assembly language can 
provide a simple way of implementing all of 
the propertics/pseudo-ops given in figure 1. 

It is important to remember that when the 
assembler is called by [, all that happens is the 
conversion of the mnemonics into absolute 
binary machine code which is sequentially 
stored. The routines will not actually be 
executed until you call them using the Basic 
statements Call and Usr. This is shown simply 
in figure 2. 

The Dim statement in BBC Basic will look 
for a continuous block of free memory^ the 
amount depending on its argument, and 
return the address of the start of this block into 
a variable. To reserve a block of 200 bytes and 
assign the starting address to the variable 
start% use Dim start% 199. 

This should be used^ before entering the 



assembler^ to bag some memory space for your 
assembled program unless you want it to be 
placed at some particular address onwards, 
which is fine if you are not bothered about it 
working across the Tube. So if your program 
is n bytes long — or less — then you need: 

DIM space% n : P% = space% 
This form of the Dim statement is not to be 
confijsed with Dim space%{n) which would 
declare an integer array called space%,n 
elements long. 

The BBC assembler supports the use of 
labels in assembly language programs and 
these are handled as if they were Basic 
variables. Therefore they must start with a 
letter and not a reserved word. When labels 
are first defined they must be preceded with a 
full stop, and finish with RTS. When they are 
referred to, the full stop can be omitted, and 
needless to say they should not be multiply 
defined. 

Since the assembler stans ofi* at the 
beginning of an assembly language program 
and proceeds sequentially through it, 
problems arise when program segments 
include instructions referring to a label ahead 
before it is defined to the assembler. 

This problem is overcome by making the 
assembler pass through the program twice, 
firstly taking note of all the labels and their 
values, which are stored in the Basic variable 
space in RAM and performing crude assembly 
of the mnemonics, translating the op-code and 
addressing mode, but not the address unless it 
is known, and substituting in any addresses it 
failed to find first time. If the assembly listing 
were examined in between these two passes, it 
would be seen that any instructions where 



forward reference occurred would have their 
address fields pointing to themselves. This 
two-pass process does not occur automatically 
on the BBC computer. It is necessary to force 
it to happen by enclosing the whole assembly 
language section in a For-To-Next loop which 
will be done twice. Of course this is 
unnecessar>' when there are no forward 
references in the program. 

The choice of value of control variable in the 
loop is determined by what you want the 
assembler to output and how you want it to 
react to the presence of errors- caused by 
forward referencing. This is explained now as 
we deal with the BBC assembler's only 
pseudo-op, OPT. 

The usual state of affairs is that we require 
different assembler output on each pass of the 
assembler, and the most common occurs like 
this. On Pass I, assembler errors are sup- 
pressed so that the process is not interrupted 
should forward references be present. There 
will be no assembly listing since the process 
will not be complete. On Pass 2, assembler 
errors are given — there are no unresolved for- 
ward references for this pass so we wish to be 
informed if any real errors are present. 

We either sec no listing at all or a full 
assembly listing of locations;^ hex code, 
mnemonics and labels. 

We control this by using the **0PT n** 
pseudo-op straight after the opening square 
bracket. The possibilities are OPT for error 
supression and no listing, OPT 1 for error 
supression and a listing, OPT 2 for error 
reporting and no listing OPT 3 for error 
reporting and a listing. This is incorporated 
into the For-Ncxt loop of the last section. 
For pass% = a To b step b-a 
I opt pass% 
1 
Next pass% 

The '*a*' is the OPT value required in the 
first pass and b is the one for the second. 
Normally, a = 0, b = 2 or 3. The OPT pseudo- 
op obviously generates no machine code of its 
own. 

The resident integer variable P% is the 

location pointer for the BBC assembler, that 

(continued on next page! 



ADC 


add with carry 


INY 


inc. y 


Tab/e h The 6502 instruction set 


AND 


logical and 


JMP 


jump 


TXA transfer x to a 


ASL 


anhmetic shift left 


JSR 


call subroutine 


TXS transfer x to sp 


BBC 


branch if carry clear 


LDA 


load accumulator 


TYA transfer y to ace 


BCS 

BEQ 


branch if carry set 
branch if equal 


LDX 

LDY 


load X 
load y 


The 6502 registers: 
accumulator (A) 8 bits 


BIT 

BMI 
BNE 


test bit 

branch if minus 
b. not equal 


LSR 
NOP 
ORA 


logical shift right 
no* operation 
logical or 


x,y index registers lx,y) 8 bits 
processor status register nvbdizc 


BPL 
BRK 
BVC 
BVS 


b. if plus 

break 

b. overflow clear 

b. b. overflow set 


PHA 
PHP 

PLA 
PLP 


push accumulator 
push processor status 
pull into accumulator 
pull processor status 


program counter 16 bits 
stack pointer 8 bits 
6602 addressing modes 


CLC 


clear carry 


ROL 


rotate left 


Name 


Example 


CLD 


clear decimal mode 


ROR 


rotate right 


Immediate 


LDX # 23 


CU 


clear interrupt disable 


RTl 


return from interrupt 


Zero page 


LDY&32 


CLV 


clear overflow 


RTS 


return from subroutine 


Absolute 


JMP &FFF3 


CMP 


compare to 


SBC 


subtract with carry 


Accumulator 


ASL A 




accumulator 


SEC 


set carry 


Relative 


BEQ &23E3 


CPX 


compare lo x 


SED 


set decimal 


Indirect 


LDA (£f2345> 


CPY 


compare to y 


SEi 


set interrupt disable 


Implied 


PHA 


DEC 


decrement memory 


STA 


store accumulator 


Zero page x 


STA 65,x 


DEX 


decrement x 


STX 


store x 


Absolute X 


JMP aPFOO^x 


DEY 


decrement y 


STY 


store y 


Pre-indexed direct 


LDA {9,x) 


EOR 


exclusive or 


TAX 


transfer a to x 


Post indexed direct 


LDA (34),y 


INC 


increment memory 


TAY 


transfer a to y 


Zero page with y 


STA 22,y 


INX 


inc. x 


TSX 


transfer sp to x 


index 





YOUR COMPUTER, MARCH 1983 97 



(continued from previous page) 
is, it always holds the value of the address 
where the next encountered assembly 
instruction will be assembled to. Thus if we 
wanted a panicular program to be assembled 
starting at location &A00 we would put, 
immediately after the For-To loop startj 
P% = &AO0. 

Alternatively, with the memory allocating 
system as previously described; 

DIM space% PROGRAMSIZE 
P% = space% 

If one wants to leave a few spare bytes in 
memory in the middle of the machine code 
program, say for workspace or constant 
storage, then another alternative to the Dim 
method described earlier would be to leave the 
assembler and increment P% by the number 
of bytes you want. You could also use the byte 
indirection operators to initialise this memory, 
e.g., ?P% = . Then record the starting address 
of for example spare bytes, room = P% before 
you increment P%. Re-enter assembler and 
continue, using instructions such as LDA 
room to access your bytes. Issue I 
Basic/assembler does no! allow the assembly of 
numerical constants straight into memory. 
To place constants in memory one should 
therefore use one of the methods already 
described. Issue II Basic/assembler does have 
the necessary pseudo-ops. These are EQUB, 
EQUW, EQUS and EQUD. 

These all take a single argimiient and put its 
value into the assembly code. 

.message EQUS "hello" 



would store at ASCII code of "h** at message, 
**e" at message + 1 and so on. 

Unfortunately, there is no easy way that 
macros can be implemented with the 
assembler contained in Issue I Basic. 
However, the EQUS pscudo-op present in the 
Issue II Basic assembler can be used along 
with the Dcf Fn statement to implement 
macros of sorts. 

A subroutine call to location &FFF4 in the 
operating system is known as an OSByte call. 
This call uses the processors X,Y,Acc registers 
to pass information to the operating system; 
Ace defines the operation to be carried out 
such as clear input buffer or alter flash rate or 
anything else that can be done as an FX call. 
X,Y contain the parameters. We could set up a 
macro which would take these three quantities 
as parameters, load them into the respective 
processor registers and call the OSByte 
routine. The macro itself would be defined in 
Basic as a function: 
DEF FNOSBYTE (A,X,YI 
IF A>127 THEN [ OPT pass% ; LDY # Y] 
[OPT pass%: LDX # X : LDA# A: JSR &FFR :] 

(dummy null string result) 
Only OSByte calls with numbers over 12 
need a Y parameter. Then, when writing an 
assembly program if wc wanted to do an 
OSByte call we would do the following; 
EQUS FNOSBYTE {&87,5,5) reads the 

character at text (5,5) 
EQUE FNOSBYTE (2J,0) gets characters 

from RS423 

Whenever the assembler encounters the 



Diagram sunrmaris/ng assembfy process 

USER 



ERROR 
REPORT 



SEMI- 
USTINQ 



FVU 

ERROR ASSEMBLY 
REPORT LISTING 




) 



i 



tNTEAMEOIATE CODE 



PASS1 



SYMBOL K 

TABLE 



3 



PASS 2 



- must bt tofctd in BBC 



EXECUTABLE 

MACHINE 
CODE PROGRAM 



ib«rt if ifror 
ID«} not 



abort if irror 



BASIC 



Figure 2, 

Calling routines, 

10 PRINT "hello" 
20 PRINT "now 
entering assembler" 
30 DIM P% 100 
40 enter assembler 
50 .start PHA:TAX: 
CMP#&33(more 
arbitrary assembly 
language) 
100 RTS* 
110 PRINT "back in 

Basic" 
120 CALL start 



above syntax the result will be the normal 
OSB)rte code sequence inserted into the 
assembly process, no string is actually inserted 
anywhere as the EQUS is fed with a null 
string by the ftinction FNOSByte which also 
manages to do a Httle assembling before it 
gives this null result. 

The ability to freely alternate between Basic 
and assembler makes conditional assembly a 
simple problem to solve. First leave Basic, use 
ihc control structures of Basic to examine the 
condition — use If-Then-Else, On- 
Goto/Gosub, and assemble the appropriate 
sections of code upon the result. If you want 
the assembler to choose between keyboard or 
joystick input in pseudo-Basic: 

assemble ..„.. 1 ; IF joystickconnecied 
THEN PROCassemblejoystickcode ELSE 

PROCassemblekeycode I : assembler 

The two given procedures do exactly what 
they say. 

Repeated assembly is easy to achieve 
because of the easy interaction between the 
assembler and the Basic interpreter proper. 
There are two kinds of loops into which we 
can put the assembly language that we want 
copying. 

Deterministic loops continue copying out 
the instructions until some condition is 
satisfied. We would use a repeat-until loop in 
the Basic part: 
assemblel : REPEAT 

[ : (insert whatever is to be repeated here. 

it may involve the control variable, and 

there should be an OPT to control 

assembler output.) : ! 

There could be some Basic instructions 

here which would effect the lo©p control 

condition. 

UNTIL condition 

I: OPT pass% :. assemble. 

Non-deterministic loops repeat the assembly 
mnemonics a fixed number of limes. For this 
we would use a For-To loop: 
...(assembler}] : FOR l%= startno. TOfinishno. 

I : OPT pass% : assembly 

instructions, could involve the control 

variable 1% if required ,..:) 

NEXTI% 

I : OPT pass% : (back to assembler > 



Figure f, f^operties and pseudo-operating 
instructions, 

■ The ability to reserve blocks of memory 
space for data, or even the program itself 
■The allowing of symbolic labels and a 
multi-pass system, usually two occasionally 
three. This includes the automatic calculation 
of relative jumps. 

■ The ability to reference the location pointer, 
a pointer to the next byte that will store 
machine code produced by the assembler, so. 
that it is possible to use relative jumps in 
programs. For instance: 

JMP . -5 
allows you to jump back to the instruction five 
bytes funher back in memory. The full point 
indicates the value of the location pointer. 
The location in memory where the next 
instruction is to be assembled can be specified 
by a statement such as: 

= 3200 

■ User output — an assembly listing should 
be given> in both hex and mnemonics, errors 
should be reported and — preferably — there 
should be a symbol table output. 



■The assembler should be able to assemble 
numerical constants, or the result of a 
numerical expression, directly into memory, 
as well as mnemonics. For example: 

label 32 

label + 1 19-5 
should result in the constant 32 stored in the 
location given by label, and 14 stored in 
label +1 

■ It should also be able to evaluate simple 
numerical expressions elsewhere, so that 

LDA# 7*2-2/2 
would assemble as 

LDA# 13 

■ There should be a facility for the creation 
and use of macros. A macro is a set of 
instructions that does a particular job, similar 
to a subroutine in that respect, and given a 
specific name. Then, whenever the assembler 
comes across that name in a program it 
substitutes it with the set of instructions to 
which the name refers. Some assemblers allow 
macros to use parameter-passing also. 

■ Conditional assembly — this facility allows 
the assembler to choose one of several 



program segments to assemble depending on 

the result of some specified test which is 

specified by the programmer and carried out 

at assembly time. 

■Repeated assembly — if a group of assembly 

language instruaions arc listed over and over 

in a program then it would be handy if it was 

necessary to write them only once and tell the 

assembler how many times to repeat them in a 

row. This is repeated assembly, for example: 

REPEAT 10 ,^^ / 

LDA somevalue 

END REPEAT ^^^ somewhere 

This might tell the assembler to write out the 

two instructions 10 times in a row and then 

assemble them* In some cases it might be 

possible for the values somevalue and 

somewhere to change each time the instruction 

pair is copied. Also, it may be possible for the 

number of copies to depend upon some 

condition rather than a fixed number, the 

difference between a For-To loop and a 

Repeai-Until loop in Basic illustrates this. 

■ The assembler should recognise all 6502 

mnemonics and addressing modes. | 



98 YOUR COMPUTER, MARCH 1983 



DOWNSWAY 



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f7 





MEMORIES 

FOR THE 

ZX81 



The Downsway 64 K Memory* slots directly on to the 
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for £1 2.50 against a Downsway 64K Memory to bring the 
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If you only want t6K of memory for your ZX81, the 
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quality and low price at only £24.95 plus p & p. 
Both memories measure only 2Vz x 1V2 x lin, and are 
supplied with a foam cushion strip to provide added 
mechanical stability. 

* Reviewed in ZX Computing Aug/Sept 1982 and Popular 
Computing Weekly 22/7/82. 



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N EW! 32K RAM FOR SPECTRUM 



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Both come with fully detailed^ illustrated instructions. 



Naturally Downsway add-on memories are fully tested and guaranteed, 
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Please allow up to 28 days for delivery. 



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YOUR COMPUTER. MARCH 1983 99 



Onch upon a time when most people stili 
thought thai a microprocessor was some fancy 
kitchen gadget, breakfast was continually 
disturbed by the rhythmic chant of children 
trying to learn their French vocabulary for 
school that morning. When wc acquired a 
ZX-81 we therefore set about using this so that 
our *snap, crackle and pop* would not be 
disturbed. 

The very limited memory of the basic IK 
unit was a severe problem, but with care 20 
words — each 12 characters long, in each of 
two Ianguagcs> could be stored for knowledge 
testing. Two separate programs needed to be 
used. The Word-loader program dimensions 
three arrays and requests 20 consecutive word 
inputs in each language. These are stored in 
arrays A and B. 

When all words have been entered this 
program must be altered to the Word-iesting 
program before Saving on to cassette by 
Goio200, Of course, the ZX-81 saves variables 
with the program but> whatever you dO| you 
must not Run this program^ as this will clear 
the arrays. When the program is reloaded it 
automatically starts, and when all words have 
been tested the program begins again* 

It is essential that CS is dimensioned — so 
that its length is fixed at 12 characters — the 
same as BS(N)j as otherwise it will be 
impossible for it to be equal to BS(N). 

Score is kept as X, which is incremented 
when line 150 is true. To conserve memorj' 
only the top two lines of the screen are used to 
display: 

TEST WORD SCORE 

YOUR TRY ANSWER 



Pause is used instead of a For-Next timing 
loop and the program entirely fills IK, 

Only 20 words could be included in this 
initial program, but different versions could be 
made containing different words. For storage 
of more words more memory is essential — 
hence the development of the Vocab 16K 
program which not only stores 220 words or 
phrases, each 25 characters long, but also 
includes a range of useful options: adding 
words, testing yourself, learning and 
dictionary. One of the most perplexing 
problems was arranging for the facility to swap 
the two languages around, whilst ensuring that 
the arrays did not become garbled. 

To initialise the program when it 
is first used, Run 8000 which Dims^ 
the arrays and sets up the other 
variables, before requesting the 
languages to be used. This was 
not included in the menu to 
avoid disastrous accidents to filled 
arrays. Do not forget you must 
never Run the program if you use 
Break to stop it. To save the program, 
plus variables, at any point Goto 9000. ^^ 

The user-friendly menu at line 20 
first prints the seleaed languages, in 
the order entered, and then the options 
available. 

If you want to reverse the language 
order you simply input X, which leads 
to the language-swap subroutine at 4000. 
This swaps M$ and NS via dummy variables 
K$ and L$. At the same time the 
language-swap status variable, T, is 
swapped between and 1 so 



that the swap status is always indicated* If 
Add-words is selected the screen is cleared at 
line 3000 and the word select subroutine at 
line 6000 called. This asks where in the main 
arrays to start and end addition, prompting 
you with the current start and end numbers. 
To delete words simply overwrite them. 

Lines 6010-6040 and 6080-6100 reject 
anything other than numbers. As the numbers 
often exceed nine this has to be done via string 
slicing, and the final strings must therefore be 
convened to simple variables by the Val 
function — 6050 and 6110. This subroutine is 
used by both Add-word and Test routines. On 
return the word display routine is called — 




MINC 



0000330000 

„ - oooooooooo 
y. oooooooooo 
^' oooooooooo 



The f6K ZX'81 language program. 

S REM uaCAB COPYRICpHT K 1- 5 L 

9 REM HCNU 

a© PRINT H« .N«^ ^VQCRBULARv"' 

30 PRIKT RT S.0;"TO TEST VOUR^i- 

ELF INPLfT "-T ' ; RT 7..©, TO CONS 

ULT DICTIONRRY INPUT "*D : RT 9 

.0; "TO RDD UOF^DH INPUT "R - RT 

ia>o,'TO uERRN iNPtnr^ 

^b PPIfJT RT £0.0. I 

^^ PC:i n£NU :s EJECTION 
50 INPUT 0« 

•T • THEN GOTO I0dd 
THEN GOTO a^O© 
THEN GOTO 3©00 
THEN GOTO 7000 

_, _^ THEN GOSUe 4.000 

110 ir oi = *'X' THEN GOTO 10 
ISG GOTO SO 
^«« REM TEST 

-OOO CLS 

1010 PRINT - H^p -- 

JL02O PRINT RT 5,0; *'FOR PiRHOOM UO 

PDS INPUT *'R— ;RT 7,0; -FDR Pf^¥i 

TICULRR UORDS XMPUT -'p--' 

XOSiQ REM RflNOOH OR PRRTZCUCRR 

1030 INPUT P» 

104^0 IF PS**P" THEN OOSUe &000 

10S0 IF Pf*i**P" THEN GOTO 90G0 

xO©0 IF P>w"R* THEN GOTO 1X00 

1O70 GOTO 104.0 

110© PRINT RT «^0;-'HOU MRN^ UORD 



©0 ir •?«* 

70 IF 0»»*'D" 

S0 IF 0»= -R' 

90 IF 0*-"L' 

100 IF 0«-"X* 



1110 
1190 
1130 
fN) > 
114.0 
lis© 

lie© 
iie9 

117© 
1179 
118© 
1190 
119S 
1$©© 
1210 
1320 
1^99 
^0O0 

£010 

a©30 



304.0 

a0B© 

a06© 

S06S 

a0e9 
a©?© 
aoa© 
a090 

^095 
a 100 
2109 

alio 



INPUT U% 

FOR N=l TO LEN U» 
IF CODE U* fN> <2© OR CODE WS 
37 THEN GOTO 1110 
NEXT N 

LET W=VRL Uf 
PRINT RT 9,£0; U 
REM RRNOOH STRRT 
LET H = INT (RND4V.* >1 
REM KJfK^l^O STRRT ECSE HfM^y^ 
IF H4U>Y THEN UET fiwH^Z 
IF n*i}>S* THEN GOTO 1180 
IF M<1 THEN t-ET H»l 
t_ET XRbH 
UET YR-M*W-1 
GOTO 5O00 
REM DICTIONRRY 
CLS 

PRINT M»^N9. 'nBI|BH|flBi";^iT 
" INPUT uriKNOUN woTtB" ;RT s©^ 




rr o«<ii 



THEN GOSUa 40© 



IF DMilt M"X" THEN GOTO £0O© 

IF Di(l>«" " THEN GOTO 10 

PRINT RT 7,l;Dt 

FR3T 

REM SERRCH RRRRY 

FOR NaX TO Y 

IF T-0 THEN G05Ue 4100 

IF 0««BJ(NJ THEN GOTO ai39 

IF T=© T*- ~- 

NEXT N 

REM NO MRTCH 

PRINT RT 10^5; "I 



rHEN oosue 4- 10© 



aia© GOTO ai4^0 
aiaa rem hbtch 
ai30 pRirrr rt 10>i;r«(nj 

2135 IF T-0 THEN GOSUB 4.100 

ai4.0 SUOU 

.^14.e FOR N*l TO S© 

.^IS0 NEXT N 

3170 GOTO a000 

3000 CLS 

301© GOSU8 6©00 

30a0 OQSUe 500© 

3030 IF T»0 THEN G03UB 4l©« 

3O40 RETURN 

3499 REH LRNGUQGE ^URP 

4000 LET K»bH« 

4.01© LET L«»N$ 

4.0a© LET M{=Li 

4.030 LET N«etK^ 

4040 LET T-r 

40S0 LET P-e 

4®0© LET r^f^ 

4070 LET E=T 

4©e0 RETURN 

4099 REM RRRRY SURP 

410© LET CSfDaR^tH) 

4110 LET Ei^BS <N) 

4.1^0 LET R% (Ni 3E» 

4230 LET SS(N)«C»C1> 

4 140 RETURN 

4999 REH UORD DISPLRY 

5000 FOR N-XR TO YR 

5010 IF T*0 THEN G05UB 4100 

S0a0 CLS 

3030 PRINT RT 5.S;H» 

S039 REH TEST BRANCH 1 

504© IF OJO-R" THEN GOTO S060 

€05© INPUT B« (N) 

80e© PRINT Rf 7^1;e»CN>;AT 10, S; 

S089 REH TEST GRRNCH S. 

5O70 IF 0«<>"R" THEN GOTO 5130 

5O0© INPUT R>(N> 

509© PRINT RT la^liR^tNJ 

5100 FOR Hal TO S0 

S110 NEXT M 

Bia© LET V-YR 

5ia5 GOTO S17B 

5130 INPUT CJtlJ 

S140 PRINT RT la^ l; C» Cl> ;RT 14^1 

;Rf (NJ 

518© FOR H=l TO 5© 

518© NEXT H 

5169 REH CHECK MRTCH 

SlTe ir C*C1I«R»CN) then let ZmZ 

*a 

S173 IF T^O THEN G05UB 4109 

SI&9 NEXT N 

S19© IF Oft*"R" THEN GOTO 10 

5199 REM Score 

5300 PRINT RT SO,S;*'mB^ - *';Z 

saio FOR Mel to 70 

Baa© NEXT M 

Sa3© LET 2»0 

S240 goto 10 

5*399 REM UORD SELECT 

8000 PRINT RT 9^0; *' STRRT UORD NU 

'• ; Y 
SO 10 INPUT X5 
SOa© FOR N=l TO LEN Xp 
6030 IF CODE XSCNi OB OR CODE X» 
(NJ >37 THEN GOTO 6010 
'*'040 NEXT N 



eoS0 LET XRaURL Xf 

8080 PRINT RT ^,StA^XB 

8O70 INPUT X» 

e&ae FOR N«l TO LEN X4 

8090 IF CODE Xf(N)<a8 OR CODE XS 
CN>>37 THEN GOTO 8070 

6100 NEXT N 

6110 LET YRaURL X« 

= lao PRINT RT 11 ^aa.ivR 

Si30 RETURN 

S5199 REM LERRN 

rO00 CLS 

701© LET XX «0 

70a© FOR N«X TO Y 

703© LET XX=XX+1 

7040 PRINT R» (N) ^Bf CN> ^ , , 

7050 IF XX =7 TH^H GOTO ^090 

7O60 NEXT N 

^O70 INPUT 0« 

■"3&0 GOTO 10 

"^090 INPUT 0« 

^lO© LET XX ■© 

7110 CLS 

7iao NEXT N 

7999 REM IMITIRLISE 

3©©0 DIM R«(aa©,a5) 
«i0i0 DIM Bfiaao.as) 
foac DIM c«ii.ssi 

502S DIM D»f25> 

O030 PRINT RT 5^0; -FIRST LRNGURG 

e ^ •• 

io40 INPUT Mg 

5050 PRINT RT 7,8; M» 

306© PRINT RT 9,0; -SECOND URNGUR 

",«?-«■" 

^O^O INPUT N» 

fC»oO PRINT RT 11.5;N» 

>O90 LET T«0 

^100 LET F-1 

5110 LET P»l 

r ISO LET Cm© 

5 130 LET X«l 

^■140 LET y-1 

3 150 LET Z«0 

3999 GOTO 1© 

S000 SRUE • VOCAB ISJB * 

9©1© GOTO 10 

UIK UOQD LORPER PROGRAM 

10 DIM Rs cao^ ia> 

a© DIM e» (a©. ia> 

30 DIM c»(i.iai 

11© FOR N«l to so 

la© CLS 

13© INPUT RS<NI 

140 PRINT RSCNl 

IS0 INPUT Bf TNI 

18© PRINT DitN) 

170 PAUSE 1O0 

18© NEXT N 

VIK UORD TESTING PROGRRH 

100 LET X=0 ^^ ^^ 

110 FOR N=l TO a© 

la© CLS 

13© PRINT R#tH) , 

18© PRINT Cffl),X;CHR* a4.N.B*'N> 

17© PAUSE l©k^ 

IB© NEXT N 

190 GOTO lOO^ 

8©© SRUE "UlS" 

ai© GOTO 10O 



100 YOUR COMPUTER. MARCH 1983 



matching word is primed, otherwise the 
**word not found*' message comes up. This 
subroutine is run in Fast mode to speed it up 
but, if you prefer waiting a little longer to 
watching the screen flash then delete lines 
2065 and 2140. 

This 16K ZX*81 program is obviously more 
useful than the IK versionj and any additional 
memory available can be utilised simply by 
changing the Dim statements in lines 8000 
and 8010. 

When a Dragon 32 was purchased and con- 
version of the ZX'8i program was considered, 
it was soon apparent that the Dragon had a 
number of distinct advantages in this learning 



5000. This is also used by both Add and Test 
routines, but with different branches. It cycles 
through the arrays from the selected start to 
the selected end — 5000^ after checking the 
status — T — of the languages M$ and NS — 
this is done at line 5010. 

If these have been swapped then the word- 
swap subroutine at 4100 is next called. This 
swaps AS(N) and BS(N) via dummy variables. 
The first language is printed and, if Add was 
seleaed - Q$=^"A" - an input - B$(N) - is 
requested and printed, followed by the second 
language, and a second input request — 
A$(N). After a delay — 5100 — the word end 
counter, Y, is reset to the new end-word 
number — 5120, and if the languages have 
been reversed from their original order, then 

'YOUR 



^^I3L^K^E 



[ 



Keith and Steven Brain's 
ZX-81 and uragon routines 
help you and your micro 
become multilingual. 

A$(N) and BS{N) are swapped back — 5175. 
When all words have been added the program 
returns to the menu. 

If Test is now selected the choice subroutine 
— 1000 — allows selection of particular or 
random words. If particular words are 
required, the appropriate Start and End 
number are selected as before — 6000. The 
random option asks the number of words 
required, W, and selects a random start 
position H at line U70, If H + W is greater 
than the total number of words currently in 
the array, Y, then H is halved — 11 80 — and 
this is repeated — 1190 — until H + W is less 
than Y, when the program passes to the word- 
display routine — 5000. Whether random or 
particular words are selected this subroutine 
operates as for adding words, except that the 
sequence is: Print first language, line 5030; 
Print AS(N); Input CS(1), Print C$(l)> print 
AS(N), the correct answer, line 5140. If your 
try was correct the score — Z — is 
incremented — 5170 — and when all words 
have been tested your final score is displayed. 

The Learn subroutine at line 7000 prints the 
first seven pairs of words and then waits for an 
input. If there were only seven words or less in 
the file then any input leads back to the menu. 
If there were more than seven words any input 
displays the next seven pairs of words. 

The final option is the Dictionary, line 
2000, which prints the languages and requests 
input of the unknown word. Languages can be 
swapped by X as before and Newline alone 
returns to the menu. When an unknown word 
is entered, it is compared with the contents of 
the appropriate array. If a match is found the 




application. The first of these was the ability 
to store data files on cassette separate from the 
program, so that the relatively short master 
program could be used for any number of 
difierent data files containing different words 
or languages. 

The second difTerence was in the Basic 
array-handling routines. Whereas in the 
ZX-81, array elements must be of fixed length, 
Microsoft supports variable length array 
elements. In practice, this means that memory 
is saved as space is not wasted on blanks 
completing unused array points. This allowed 
the program to be more flexible and the length 
of phrases to be up to 255 characters. 

The third point was the ability to control a 
cassette recorder and TV sound with the 
Motor and Audio commands, making in- 
clusion of a speech track possible. The fourth 
point was the high-resolution graphics which 
allowed display of non-standard characters 
such as accents. 

Finally, multiple-statement lines make com- 
plex programming easier and sound and 
colour can be used to liven up the proceedings. 

The same outline skeleton was used, but 
with certain additions. As the data is loaded 
separately, the program always initialises the 
arrays and other variables and requests the 
languages — line 1 1000. The menu, line 1030, 
is left via InkeyS, line 1050, rather than Input, 
and the ASC value of Inkey$ is used to sound 
a note to remind you of your choice. Where 
lower-case letters, which are inverse on-screen 
are used, unsightly gaps between words are 
avoided by using BLS, which is set to 
CHR$(128), instead of a space between words. 



A new cassette Load-Save routine is 
included — Line 8000. Selection of Save — 
8010 — requests File-name, Start and End 
positions. The cassette motor is turned on to 
allow you to position the data tape and when 
you are ready a data file is opened and the * 
languages (M$, NS), swap status (T) and array 
contents saved. Selection of Load also requests 
filename, Start and End positions. These peed 
not be the same as those used when these 
words were Saved, but can be offset so that 
words can be moved around the arrays. 
Languages — M$ and N$ — swap status, T, 
and words are then read in 8030. 

The Audio routines — 9000 — allow Saving 
and Loading of both data and voice, 9030. If 
Save is selected a data file is opened and loaded 
as before, line 9060. When Saving is complete, 
instructions are given to alter the cassette 
leads at line 9080. Each selected word is now 
displayed — Line 9100 — and, when a tone 
sounds, the recorder is automatically turned 
on and you speak the word. After a short 
delay, the next word is displayed and the 
cycle continues until all selected words 
have been dealt with. In this way, a 
spoken-word file follows immediately 
behind the word data file. When Play is 
selected, the data file is read back — 
line 9120 — and speech playback only, 
or speech and display can then be 
chosen. 

If the display and speech option is 
I chosen, the first language and first 
word arc displayed, and the 
recorder automatically plays the 
first spoken word through the 
TV speaker. 

The program as described so far is excellent 
as long as neither of the languages uses 
accents, but even this difiiculty can be solved 
if the characters arc drawn on the hi-res screen 
instead of being printed — see Your Computer^ 
February 1983. 

This approach requires addition of 
appropriate character-drawing lines — 31-90 
— and handling routines. The litile-used 
upper case # , $, %, and & have been replaced 
by^,^^ and ^, for French text but any keys can 
be modified in this way. We have stuck labels 
on to the front edge of these keys to show their 
new functions. 

Line 20 checks that a character is valid and, 
if SO5 line 30 selects the appropriate Draw 
subroutine. Two different types of the hi-res 
display are needed — 100 — according to 
whether an existing string is to be read or an ' 
Input is to be made. These are indicated as 
MD=1 andMD = 2. 

If MD = 2, line 300, a string - RS :;- is 
simply sliced and each character drawn in 
turn. If an Input is required, life is more 
difficult. Only InkeyS can be used without 
losing the hi-res display. If the InkeyS 
character is Enter and any character has 
already been loaded, this is read as the same as 
a normal Enter and Input mode is left. If 
InkeyS is not backspace — left cursor — the 
equivalent character is displayed, and then 
added on to the end of TM$ — a temporary 
storage string. 

If backspace is used, the previous character 

is erased from the screen. Once the handling 

(continued on page 103) 



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102 YOUR COMPUTER, MARCH 1983 



(continued from page 70 f I 

routines have been sei up^ those program lines 

which are to display accented words must be 

modified. 



The modifications have the following form: 
Select mode: (if MD -2 then fill RS); set Screen 
position: GOSU8100 and repeat. 

Screen position is set by drawing a line of 



length (zero) at the appropriate point on the 
screen. Addition of this accent facility 
considerably enhances the value of the 
program. | 



Vocab 32, 

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YOUR COMPUTER MARCH 1983 103 



i 




M.C. LOTHLORIEN 

Fed up with Space Invaders? Fed up with moving N.S.E.W, in seem- 
ingly endless Adventure games? — then why not try our exciting range of 
challenging war games for the SPECTRUM/ WK ZX81/ DRAGON 32 

1. TYRANT OF ATHENS 

Can you survive long enough to turn Athens into the most feared state in the 
Mediterranean? Train troops, build warships, fight battles by land and sea against hostile Greek States and the vast 
Persian Enr\pire. Many more features in this very addictive game. 

Price: DRAGON £6.95 ZX81 £4.50 SPECTRUM £5.50 

2. ROMAN EMPIRE 

Your aim is to conquer the hostile countries surrounding Rome. Build armies, appoint Generals and 
fight campaigns. This challenging game takes full account of morale, fighting efficiencies, leadership ability, etc, 3 levels 
of play. 

Price: ZX81 £4.50 Spectrum £5.50 

3. PELOPONNESIAN WAR 

Set in Ancient Greece from 431-404 BC, covering the Great War between Athens and 
Sparta. Your goal is a final victory over the Spartans but you will need all your skill in a combination of diplomacy and 
military force before you even stand a chance. 3 levels of play. 

Price ZX81 only £4.50 

4. SAMURAI WARRIORS 

How would you have fared as a Samurai in 13th Century Japan? Face challenges from 
Samurai and bandits- Are you a survivor? Or will you be forced to commit ritual suicide? 7 levels of play, a most fascinating 
game. 

Price: DRAGON £6.95 ZX81 £4.50 Spectrum £5.50 

5. WARLORD 

A challenging game of analytical skill set in 13th century Japan. You control a village and must meet 

attacks form other armies, combat challenges from other warlords and their Samurai, attack and defeat pirates, make 

raids for gold or slaves and feed your village. 

Price: ZX81 £4.50 Dragon 32 £6.95 

Cheques and PC's please, made payable to; M.C. LOTHLORIEN 
4 Granby Road, Cheadle Hulme, Cheadle, Cheshire SK8 6LS 



16K BUDGET PAK 

JRS 1 6K RAM AND FREE ALIEN ATTACK plus either 

BATTLESHIPS or GAMES TAPE W 

SAVE £8.65! Total package price only £27.75 




64K BUDGET PAK 

JRS 64K RAM AND FREE ALIEN ATTACK plus either LOST 

ISLAND or BATTLESHIPS 

SAVE £7.95! Total package price only £64.90 



i m 
f 4 



^ f I 

I » I 



# 4 m jf 



ZX81 



Hardware 

Econotech 16K RAM iuncased} , Only £20.95 

JRS f 6K RAA4 ,„.. Only £26.50 

JRS64K RAM ..„ Only £62.95 

Software 

ProgfamniefsToo/kJt(I6K) Only £4.95 

Graphics Toolkit ( 1 6K) Only £5.95 

lost Island (16K) Only £4 95 

Games Tape fl( 1 6K) Only £4.95 

Battleships (1 6K) „ Only £4.95 



SPECTRUM 



A full range of software and hardware are available. Trek the 
coupon below for your free ?983 catalogue and erKlose a large 
stamped addressed envefope. 



I wish to order the following: 



i_ I6K Budget Pak with Battleships ....... 

__ 1 6K Budget Pak with Games Tape U 

C 64K Budget Pak with Lost Island , 

C 64K Budget Pak wrth Bartfeships 

D Econotech 16K RAM 

D JRS 16KRAM 

G JRS 64K RAM 

C Programmers Toolkit (1 6K) 

G Graphics Toolkit (16K| 

Z Lost Island (1 6K) 

g Games Tape 11 (I6K1 

J Battleships (T 6k) 

C 1983 JRS Catalogue 



Tick as applicable Total (Including VHT & P&F] 



Only £27 75 
Only £27 75 
Only £64 90 
Only £64.90 
Only £20.95 
Only £26 50 
Only £62.95 
Only £495 



Only 
Only 
Only 
Only 



£5.95 

£4.95 
£4.95 
£4.95 



Free 



Name ... 

Address 



Age 



19 WAYSIDE AVENUE, WORTHING. SUSSEX. BN13 3 JU Telephone: 10903) 65691 



Post to: JRS SOFTWARE, Department YC 

19 Wayside Avenue, Worthing, Sussex BN13 3JU 



104 YOUR COMPUTER. MARCH 1983 



ATTENTION ALL DRAGON OWNERS! 

FED YOUR DRAGON LATELY? 

THEN TEMPT HIS TASTEBUDS WITH THE MEATIER MORSELS FROM ActJVe Softwafe! 
OUR POLICY IS 100% CUSTOMER SATISFACTION — TRY US! 

8. CHALLENGING GAMES ON ONE CASSETTE — EACH GAME INCORPORATING THE 

SPECTACULAR FEATURES OF THE DRAGON 32 : — 

• BRILLIANT COLOUR * * IMPRESSIVE HI -RES GRAPHICS* *EXCITING SOUND EFFECTS* 



1) Interplanetary Trader — 20k4. ! 

The year 2283. Occupation: - Space Trader. Tour the Solar 
System in this real time game. Very challenging and 
^ feature packed. 

3) Wumpus Mansion — 20k + ! 

Incredible Fun!! Outwit the Wumpus (if you can....) and 
raid the treasures of the Mansion. But don't trigger the 
^. . ,. , — TIME BOMB! — 

5)Hi-'Lo — 20k+! 

is it skill or is it luck?? Turn £50 into £1,000,000 with 
this simple, yet highly entertaining game. Supersound. 
^x M * i ■ » Brilliant colour, and graphics. 

7) Atom Hunt 

Full colour, sound, and graphics add to the excitement of 
this addictive game of deduction. Features:* 1 to 4 
players: individual scores and ratings. 




2) Execution — 20k+! ' 

A hangman style game with a difference. Play the 
computer or an opponent. Lots of extra features. Good 
^^ .... . graphics and sound, 

4) Wipeout 

Compulsive, exciting, challenging game of fast reaction. 
Begins easy but gets progressively harder With sound 

and graphics. 

6) Snail Pace 

Announcing: - SNAIL DERBY- f Supei entertainment! 
Computer calculated odds and form. 2-8 snails per 
race. Beat the bookiel Full Graphics. 

8) Air Assault 

Blast the skyscrapers with ultra -high explosive bombs 
and clear a space to land your crippled aircraft t>efore 
crashing. Hi -res graphics and sound. 



y^% * AH 8 programs supplied for the realistic price of just: — 

i^ ^V^ * All 8 programs double recorded on our own quality tape. 

J^ ^ * No -quibble replacement guarantee. * 48 hour dispatch. 

*^^W\N^Send Chq/RO. tO: Active Software, Temple House, 43-48 New St., Birmingham B2 4LH. 






£5 



75 



♦25p 
P& P 



ifv 



HOME & BUSINESS TECHNOLOGY 



^0 



Probably the widest selection^^^^^ — ^of software available by maiJ order. 

All the lop manufacturers including Acorn Soft, UK (Sinclair), Superior Software, Bug Byte, Prograin Power, Hessel, Procyon. 



1 HERE IS A SELECTION — 




Pecko Computer 


9.95 


Junior Maths Pack 


6.84 


PhUoM>phcr'$QticM 


9.95 


Planetoid 


9.95 


Meteors 


9.95 


Arcadians 


9.95 


Swoop 


7.99 


Chess Model B 


7.99 


Space Invaders Model 6 The best 


«.95 


Atlantis — Superb fast Action 32K 


6.95 


H)perdrivc32K 


5.95 


Strfttobomber ^ _ . , .. ., 


6.95 


Send SAE for full list. 





1 HARDWARE EXPANSION - 

Sound pick -off modulctsimpletoru) 
Ampli Her and loudspeaker suitable for above 
Light pen 
X-Ydigitiser 


6.95 
37.50 
34.50 
80.00 



1 SUPER ACCESSORIES — 




Cover Polyester Couon 


3*97 


Cover Soft PVC 


4.45 


Caro-ing Case for Computer, Cables, Cassette/ 
E>iic Drive 


55,20 


Carrying Case a soft supported nylon version 
of above 


23.00 



BBC models A & B in stock: 

A- £299 B-£399 



1 -DISK DRIVES FOR BBC 

BBC lOOKSingIedrive( Requires discs (a)) 


265.00 


TORCH Z80 800K Disc pack includes Z80 proc'r 




--64K(b) 


897.00 


BBC/LVL 200K Twin Drive (a) 


397.00 


TEAC 200K Single Drive (a) 


304.75 


TEAC 400K Tn* in Drive (a) 


569.25 


TEAC 400K Single Drive(b) 


396.75 


TEAC 500K T^in Drivc(b) 


711.85 


Connecting cable for TEAC drives 


17.25 


(a) SCOTCH Singicsidcd discs Boxof 10 


28.75 


(b> SCOTCH Doublesidcd discs Boxof 10 


39.80 


- - nn/^ iipr^DAfir^ 


Full upgrade kit (fitting £3 1 .00) 


69.00 


Kjc ini«rr«ce((iiting £ 1 J .00) 


109.25 



T>^ iboivt pTKn &r« VAT tiK}uii««. Add f ! .00 pftp !«< ofdcf « i^om £100.00 And £10.00 

(S«curkor dd^rry} fof ord«tt a^vc £100.C0. 

Aeetu iA4 B«rd«>v«rd accepted oo at! it«fnf tMtpi 89C compacts. 

ELTEC COMPUTERS 

217 Manningham Lane, Bradford, BD8 7Hri. 

Tel (0274) 722512. 



YOUR COMPUTER. MARCH 1983 105 



4 



Sofftimare for the BBC micro«MMnpiiter 



f i f JA 'f 




fOftlKBBCIicnxoniNitti McnMB 



Mode 2 graphica a machine code 
game much like the Gafaxians 
found in the arcades — very fast and 
also works with joysticks 





C7.80 +VAT 




High speed and high resolution 
graphics are combined in this game 
to produce an exciting game — 
afmost identical to the original 
arcade version 



Z7.80 +VAT 



Another game that has received 
very favourable reviews - Fast and 
addictive 

£7.80 +VAT 




The word processor for the BBC 
machine. 

This ROM based word processor 
has received superb reviev^s* 
Supplied with full spiral bound 
manual and cassette containing an 
example document This is available 
from stock now — any quantity 

£39.00 +£1,50 p&p+VAT 



We give very generous 
trade discounts 



Our tapes are guaranteed to 
work on all Operating Systems. 



High resolution graphics with 

thousands of skill levels — more ^^^^^^mm mwm^^m^ 
features than any other chess game » ^J M^^yB l^rFP j . 
£ 1 0.00 + VAT. *i*#l«H- W ■ ■Slim.^g^ 



PLUS MANY MORE 



ii'JjJ'^- 



'yjt 



BJ 16 Wayside,Chipperfiekl/ Herts, WD49JJ.tel(09277)69727 




TOP QUALITY MACHINE-CODE 
PROGRAMS 



FOR THE 



njn]0 



MICROCOMPUTER 



DISC-BASED SOFTWARE 
AVAILABLE NOW! 

At last . . . high quality software is available on disc for the B.B.C. 
microcomputer now! 

Our programs are ready for despatch on quality 5.25" discs at only £9.90 for 
each program. 

Afternatively, all six programs (together with a special menu-type selection 
program can be supplied on one disc for just C49.90. 




CENTIPEDE 132K) £e.50 (on cassette)/ £9.90 (on disc) 
Incredible arcade type game featuring mushrooms, flies, srtatts, spiders, 
and the ccntipodos of course. Excellent graphics and sound. 6 skill levels, 
hi- score, rankings, bonuses, and increasing difficulty as the spiders 
become more active and the mushrooms increase. 



SPACE FIGHTER(32K) £6.50 (on cassette}/ £9.90 (on disc) 
Afcade*stYle game based upon features from DEFENDER and 
SCRAMBLE. 5 types of menacing alien fire at you and may attempt to ram 
you. Separate attack phases, fuel dumps, asteroids, repeating laser 
cannon, smark bombs, hi-score, ranking, 6 skill levels, bonuses. 



FRUIT MACHINE (32KI £6.50 (on cassette),' £9.90 (on disc) 
Probably the best fruit machine implementation on the market. This 
program has it all . , . HOLD, NUDGE, GAMBLE, moving reels, realistic 
fruits and sound effects, multiple winning lines. This is THE fruit machine 
program to buy. 



GALAXIANS (32K) £6.50 (on cassette)/ £9.90 (on disc) 
Fast action version of the popular archade game. 4 types of Gatsxtan {in 3 
initial screen formations) swoop down indtviduaily or in groups of two or 
three. 6 skill levels, hi-score, ranking, bonus laser bases, increasing 
difficulty, superb graphics and sound, 

INVADERS (32K) £6.50 (on cassette}/ £9.90 (on disc) 

Superior versfon of the old classrc arcade game including a few extras. 48 

marching invaders drop bombs tnat erode your defences, and 2 types of 

spaceship fly over releasing large bombs that penetiate through your 

defences. Hi-score, increasing difficulty, superb sound effects and 

graphics. 

ALIEN DROPOUT (32K) £6.50 (on cassette)/ £9.90 (on disc) 

Based upon the arcade game of ZYGON, but our version improves upon 
the original arcade game itself. You have to shoot the aliens out of their 
"boxes" before the "boxes" fill up. Once full, the aliens fly down 
relenttessty, exploding as they hit the ground. Suitable for use with 
keyboard or joystick. 




SUPERIOR 
SOFTWARE 



Please add 50p per order for PEfP + 15% V.A.T. 



Telephone: 0S32-842714 
Dept. YCS, 69 Leeds Road, Bramhope, Leeds. 



We pay 25% royalties for high quality programs. 
Dealer enquiries welcome. 



106 YOUR COMPUTER, MARCH 1983 



EASf ATOM COD 




If your Atom seems hostile 
about giving away 
information, Vincent 
Fojut's error- 
message handler 
might not 
exterminate all 
errors — but should 
certainly 
help you 
correct them. 



Putting it kindly, the error codes 
provided by the Acorn Atom's 
standard error handler can be rather 
unhelpful at times. Just what is error 
191? Newcomers lo the machine 
need a little more encouragement 
if they are not to be put off by 
their inevitable mistakes. Even the 
more experienced Atom user can 
save himself the frustration of 
checking on the meanings of the less 
frequent error codes. 

The short machine-code program — 
listing 2 — alleviates the problem by 
providing an English language error-message 
handler in place of the standard error routine. 
For maximum utility^ the normal error codes 
and Basic line number references are still 
provided. Total memory requirements^ for the 
machine code and error-message data table, are 
in the order of 1.25K, though this will very 
depending on the length and number of the 
error messages stored. 

Before we can print the English messages 
for each errofj we first need a convenient 
means of entering them into the machine. The 
Basic program in listing 1 facilitates the 
required data entry. As you can see from the 
short sample run in figure 1, the entry 
program prompts the user for an error code, 
which must be between and 255 inclusive, 
and then its associated error message is 
requested. 

As a helpful starting point> a list of all the 
operating system errors, and their respective 
translations into English, can be found in the 
Atom user manual, Aiomk Theory and 
Pracikey on pages 205 to 209. The meaning of 
each error can be typed in verbatim, if desired. 
There is, however, nothing to stop you 
modifying these messages — shortened 
lengthened, rephrased or typed in Swahili — 
to suit your own particular requirements. 

To terminate data entry, type 999 in 
response to the Error number? prompt. 
Alternatively, the program will terminate 
automatically if there is insufficiem memory to 
store another error message — see lines 340 to 
360, listing 1. 

When data entry is completed, the program 




returns the number of messages stored, and 
prints a suitable COS command to save the 
entire message table for future use. The lazier 
ones amongst you, who wish to avoid 
retyping, can enter this command by using the 
cursor*control and Copy keys. 

Once the data table has been created and 
stored, the Basic program is no longer 
required. It can safely be overwritten by your 
current program or application. Remember 
that if you wish to use mode 4, the highest 
resolution graphics, you will need to store the 
machine-code routine and the data table in 
lower text space, say, at # 3700 onwards, as in 
the program examples. If mode 4 is not 
required, then anywhere in the upper 3K of 
graphics RAM - '# 8C00 to # 97FF - can be 
used. 

Figure 2 shows how the messages are stored 
in the data table. Each entry consists of an 
error number, followed by a message in 
ASCII. Both upper- and lower-case ASCII 
characters are permitted. Note, however, that 
the byte containing the first character in each 
ASCII string has its top bit set to 1 . This gives 
the new^ error routine a convenient means of 
detecting the end of any message string — it ] 
need only look for a byte with a negative value. 

The end of the message table is marked by 
two consecutive bytes of value zero. You may 
perhaps wonder why two bytes were 
necessary, as opposed to just one, since there is 
no Basic error with a number of 0. The reason 
is that the value zero could itself be a valid 
error code — as could any eight-bit value — if 
the routine were to be used by machine-code 
programs. Since no restriction has been placed 



on the order of error numbers during data 
entry, it follows that an error code of zero 
could occur anywhere in the message table. A 
double-byte end-of-table marker avoids any 
such potential confusion. 

Listing 2 details the modified error-handling 
routine. The Break vector at # 202, # 203 is 
modified so that whenever a 6502 BRK 
instruction is executed — for example during 
the normal trapping of a Basic error — 
processing is rerouted via this program. The 
routine scans through the user-defined error 
message table until a match is found for the 
current error number stored on the processor 
stack. As soon as a match is found, the 
appropriate message string is printed. This is 
followed by the standard Atom error output, 
so that you can isolate the offending Basic line. 

If no match for the error code can be found, 
the program jumps straight into the normal 
Atom error routine. 

In testing this routine, I hit upon what 
appears to be a little-known fact about the 
Acorn Atom. The BRK vector — BRKVEC at 
#202, #203 — unlike the other operating 
system vectors, cannot be changed by Basic in 
direct mode. To demonstrate this, try entering 
the following .directly — that is, without line 
numbers; 

?# 204= # AB;?# 205= # CD change IRQ 

vector 
P.&?# 204,£f?# 205 should give AS, CD - 

that Is, vector changed 
Press Break to restore the IRQ vector*s 
original contents, # AOOO. However: 
?#202=#AB;?#203= # CD change BRK 

vector 

(continued on page 709/ 

YOUR COMPUTER, MARCH 1983 107 



e. 



ZX Spectix^bYSTIX ! vie 20 



Software 




FROM INTERCEPTOR 



M 



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SOFTWARE FOR THE UNEXPANDED VIC 20 



FROG 



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An amazing version of Frogger in the unex- 
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PUCKMAN - MACHINE CODE 
The old favourite back again. Joystix or key- 
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ALIEN ATTACK 




VIC 



RESCUE 




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This program is designed around a penny slot 
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ALiEN ATTACK - MACHINE CODE 
You are under attack from an immense force. This 
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VJC RESCUE - MACHINE CODE 
Your Planet is under attack by a fourth dimen- 
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This is the most amazing alien game ever seen on 
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Can you defend your planet from an alien invas> 
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Quantity 



Item 



Joystix Board tSpectrumJ 



Galaxzions Vic 20 



Space Bugs Vic 20 



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Alien Attack Vic 20 



Bomber Vic 20 



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Penny Siot Vic 20 



Wordhanger Atari 



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CRAZY KONG 
Unexpanded VIC 20 

FANTAZIA 
Unexpanded Vic 20 

WATCH THIS SPACE 



JOYSTIX SHOWN NOT INCLUDED 



108 YOUR COMPUTER, MARCH 1983 



(continued from page 107} 

•P.ef?# 202,&?# 203 stHI gives D8.C9 - that is, 

vector not changed 
As far as our new rouiinc is concerned, the 
cffecls of this are twofold. Firstiy, any 
program which uses the new error handler 
must immediately alter the BRK vector to the 
new start address. Secondly, the new messages 
will not be displayed for Basic errors caused 
by a direct-mode line, unless the same Basic 
line redirects the BRK vector first. In practice, 
this second point is no real problem. Any 
direct-mode error will obviously be due to the 
line jusi entered and should, therefore, be 
relatively easy to identify. 

Now that you have entered or loaded your 
message table and modified error routine, how 
do you use it? Figure 3 shows a simple Basic 
program which causes the new error handler 
to be executed. Note thai the very first thing 
the program does is to change the BRK vector 
— we assume that the machine code has been 
stored at address # 3700 onwards. 

Once this is done, you may enter your Basic 
program as normal. You have the added 
assurance that when run> your program will be 
able to identify any errors in as precise and as 
meaningful a way as you choose — see the 
sample run in figure 3* 

Machine-code programs may also use the 
error handler to good effect. As an example, 
consider the program in figure 4, The routine 
adds #40 to the value stored at address 
# 0090. If the byte at this address is # 3F or 
less, then the sum of the addition is stored at 



Figure 2, 



aw*- *5 <Huc p;Mii»*-f pi»t •'•^ ^**r> 



t 



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f 



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n 



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figure 4. 




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ae FOR N-e to ii luh)«i; next n 


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40 C 




50'LL0 LDR 80 \stt \iP \ 


60 


STfl §202 Nvtctor 


70 


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80 


STfi •203 \trr. routint 


90 


\C start tddrtss 


£08 


\of §3700 asfuntd) 


110 


LDA 190 


120 


CLC 


130 


RDC Sir40 


140 


8VS LLl vovtrflow? 


150 


STR #91 


160 


RTS 


170'LL1 


BRK \ IRQ to 9rr. 


180 


\hinrtdltr. 


190] 




200 MEXT N> END 


— - < 'RUN'' to AsstmbU nachiifte codt ) — 


- Sj^mpU 


run fl - <no ^rror) 


>?I90»«3F 




>LlNKi3600 1 


>P,lr?f9l 


/ 


7F 




- S«i#lt 


run 8 - (ovtrflow) 


>?»90»i*40 




>LINK#3600 


$i^fl«d JirithMtic ovtrflow 


ERROR 22 





address #0091, as in Sample run A. If the 
byte is # or greater^ then the addition will set 
the processor's overflow flag. When such an 
overflow occurs, a suitable error message can 
be displayed by invoking the new error 
handler via a BRK instruction — see Sample 
run B. 

The value of the error code generated by any 
BRK instruction is calculated by adding 2 to 
the BRK instruction's address, and shedding 
the high byte of the result. In the example in 
figure 4, the BRK will be located at #3614, 
which generates an error number of 
# 3614 + 2= # 3616 = a low byte of # 16 or 22 
decimal. If a suitable error message is added to 
the message table for this error number, then 
it will be displayed whenever the overflow 
occurs. 

Note that, like its Basic counterpart, the 
machine-code program firstly redirects the 
BRK vector. This must always be done, 
unless the machine code is being called from a 
Basic program which itself modifies the 
vector. 

The more adventurous may like to modify 
the data-entry program so that control 
characters may be easily embedded within the 
error-message strings. This could for example 
enable you to clear the screen before 
displaying certain error messages. 

In addition, the size of the message table 
could be reduced to some extent through the 
use of text compression techniques, with text 
expansion rouiinc in the new error handler. 
Concise message phrasing also helps. B 



Listing 1. 



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>RUN 

l#€H PROflPTEO, ENTER RN ERROR 
HO., FOULOMED BY m RSSXlftTEO 
ERROR MESSftGE OF YOUR D40ICE. 
TO TERHlNfiTE, EHTER AN ERROR NO. 
OF '959' 

STftRT RDDRESS OF !€SSflCE Tfl&LE <HEX> ?i38e0 

ERROR NUttB£R?69 

ENTER MESSAGE 

tlUeQAl FOIH sUUfttnt 

ERROR NUHe£R?a2 

ENTER MESSAGE 

?Si9n#ci Jrithwttic ovtrflow 

ERROR NUt1BER?9l 

ENTER MESSAGE 

?No h#x*dtcin*l tHiwbtr t^t^r "I* 

ERROR NUriBeR?959 

HUHSER OF EHTRIES - 3 

*SAVE"ERRTft8"38C0 3854 



Figure 3. 






10 ?#202«0i?#203*#37; 

20 

30 fl«#7F 

40 B=»T 

50 C=fl+B 

ee PRINT C 

70 END 


REM SET UP VECTOR FOR NEW ERR. ROUTINE 
REM (START flOORESS OF #3700 ASSUMED) 

REM THIS MONTH'S DELIBERATE MISTAKE! 


>RUN 






No hexadecimal 
ERROR 91 LINE 


nunber after "#" 
40 



YOUR COMPUTER, MARCH 1983 109 




Outstanding Features 

• Super strong nylon and steel construction, built to last. 

• A total of 8 directions plus 2 large fire buttons. 

• Arcade proven moulded leaf switches ensure incredible reliability. 

• Connplete with self contained boxed interface which simply plugs 
into the Spectrum expansion port (with or without printer). 

• Easily programmed in BASIC or M/C. 

These arcade games, designed exclusively for the Joystick by leading 

software houses, are now available for Spectrum: 

3D.Tunnel M/C I6/48K £4.95 

Gulp Man M/C I6K £4.95 

Time Gate M/C 48K £6,95 

Meteroids M/C I6K £5.95 

Spooky Man M/C I6K £4.95 

Watch this space for more software! 

HEmparron 

■^ MICRO ■ ELECTRONICS 
1 80a Bedford Road. Kempston, Bedford MK42 8BL 



I I wish to order 



Quantity 



Item 



Post & Packing 



Price 



£1.00 



Total (VAT inclusive) 
Cheques/Postal orders should be made payable to 
Kempston (Micro) Electronics 

Nanne^ 



Address . 



Post to Kempston (Micro) Electronics, Dept YC4 
180a Bedford Road, Kempston, Bedford MK42 8BL 



EDUCATIONAL COMPUTmG 



Suit 
chiWren 

ages 5-H 



on the 



ZX81 



No comparabte 
co/tecrion 
f 'fers so much 
for so Uttk 



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r«cofr)m«nd6d by. __ _ ^^.^ ^ 

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And fou 0on*t #v«/t nmma to know progrmmmtng. 
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tHm pfomof imsrttktg thfough intmeM;Uon 4 diBoovmy, 

I nc hides - 



TORTOISE 
A simplified 
version of the 
/^y^i i^^^^mi ^ famous Turtle 
of (mujU) l^H^V H progrannnrie 

COOED MISSILE 



SPECTRUW 



AH pfograms 
fit IK 

Creative use 
graphics 



Many innovative 
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FuHy documented 

includes many 
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Combines the 
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£5-95 only 

pap«rb«cK 110 pag«9 
pMj3 Sp«ctrum supplement 

Graph-pbtter # Htstogrdm • Simon-spell # Sk&tchLudrd f Tfmes-uble # Sets 
Series -quu # XYcoordmates # Count # Equal ions # Areas # GuesS'd-\Aikfm 
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Temperature # Clock # Money # Snake 
Mdslermmd# Number shoot • 4^26 more 

\jq: |piease send me ...copies Educare's 50.1 

IEDUCARE h enclose cheque postal order for £...,,,. ■ 
139a Sloane St ^^3^3 | 

I I 



EDUCARE 



Lot your child benefit early - S^nd now 



r 9 FORTH 



"r q FORTH'* runs on 16K or 32K 
830 micror'and costs £15, lit 

* follows the FORTH- 79 STANDARD 
and has fig-FORTH facilities; 

* provides 260 FORTH words; 

* IS infinitely extensible; 
^ has a full-screen editor; 

* allows full use of the M*0.S; 

* permits use of all graphic 
modes, even 0-2 ijust!); 

* provides recursion easily; 

* runs faster than BBC BASIC; 

* needs no added hardware; 

* includes a 70 page technical 
manual and a Summary card; 

* has hundreds of users> 



FORTH 
TOOLKIT 



Level 9 Computing are pleased 
to announce a new toolkit for 
"r q FORTH*' on 32K -eec micros. 
It costs only £10 and adds the 
following facilities to FORTH: 

* a 6502 assembler, providing 
machine-code within F0f5TH; 

* turtle graphics* giving you 
easy-to-use colour graphics; 

* decompiler routines^ allowing 
the versatile examination of 
your compiled FORTH programs; 

* tne full double-number set; 

* an example FORTH progran; and 
demonstrations of graphics; 

* other useful routines. 



Aci/com 

Extension Basic , £15/£30 ROf-t 
Adds 30 new keywords to BASIC 
Compression Assembler 2 « £12 



Sr>all sour*:e ^ high speed 




Asteroids ni/c,g £7,90 

Gala at y Invaders • m/c,g £5.90 
Missile Defence . m/c»g £7,90 

Super Gulp eb,g £4.90 

S-gamcs cassette . misc £5.90 
(FULL RANK3E IN CATALOGUE) 




ofooeot a R.es 

Spectrum 0][D[3 ACI/COilf 

1) COLOSSAL AOVENTURE : The classic mainframe game "Adventure" 



with all the original treasures t creatures + 70 extra rooms. 

2) ADVENTURE QUEST : Through forest, desert, mountains, caves, 
water, fire, moorland and swamp on an epic quest vs l^rSLnn^, 

3) OUNGEOf^ ADVENTURE ; The vast dungeons of the Demon Lord have 
survived His fall. Can you get to their treasures first? 

Every Level 9 adventure has over 200 individually described 
locations ^t\<i is packed with puzzles - a game can easily take 
months to complete. Only sophisticated compression techniques 
can squeeze so much inl Each game needs 32K and costs £9,90 



ALL PRICES INCLUDE P^P AND VAT - THERE ARE ISO EXTRAS. Please 
send order or SAE for catalogue, describing your micro, to: 

LEVEL 9 COMPUTING 

Oep^r^^2^^uQhende^^oad^^ig^^ycof^^ 



1 10 YOUR COMPUTER. MARCH t983 



BASIC DICTIONARY 

This dictionary, compiled by Tony Edwards, will explain the function of common Basic words as 

used In popular machines, enabling you to work out your own machine's equivalent. A useful 

complement to our recent series on Basic dialect translation. 



BASIC DICTIONARY 



PROC A reserved word which starts a user- 
declared numeric procedure on the BBC 
Micro. 

PTR An unusual statement pair used by the 
BBC Microcomputer to allow selection of 
the next byte to be transferred between 
program and file, giving random type 
access. 



R, The TRS-80, level 1> and Palo Tiny 
Basic abbreviation for the RUN command. 

RAD A function which converts degrees to 
radians. 

RANDOM A statement which resets the 
seed to be used for the random number 
generator. Its use — usually without 
argument — allows different pseudo- 
random series to be generated each run. 

RANDOMISE The standard ANSI word 
- though little used - for the RANDOM 
functions. 

REA The PDP-80E abbriviation for READ. 
The same abbreviation followed by a full 
stop is used in TRS-80 level 1 and Palo 
Alto Tiny Basic. 

READ A standard ANSI statement which 
causes data to be read from a Data line 
elsewhere in the program. The read data 
are assigned to variables. 

RECALL The Apple 11 function which 
causes the computer to input data from a 
cassette drive. 

RENAME The statement used to rename a 
current file. It requires two arguments, the 
old name and the new name. 

REM A standard ANSI word used to 
indicate that the interpreter should ignore 
the following line or part of a line* 

REMARK The same statement as REM. 

RENUM The Microsoft abbreviation for 
RENUMBER. 

RENUMBER The command which re- 
numbers the lines of a resident Basic 
program and simultaneously adjusts the 
addresses to Jump commands to maintain 
program logic. 

REPEAT . . , . UNTIL A BBC Micro 
statement. It produces a loop which is 
repeated until the specified condition is 
true. A single REPEAT may have multiple 
UNTILs. This statement is not often 
available in Basic but can be simulated — 
see Your Computer^ June 1982 page 44, 

RES The PDP-8E abbreviation for 
RESTORE. 

RESET The TRS-80 statement which 
switches off a specified pixel. 



REST. The TRS-80, level 1, abbreviation 
for RESTORE. 

RESTORE A standard ANSI word which 
causes the DATA pointer to be reset. This 
has the effect of causing the next READ 
statement to operate on the first of a 
program*s data. In some machines a partial 
RESTORE is possible. 

RESUME The statement used as a target of 
an ON ERROR GOTO routine. It directs 
the computer to continue execution from 
the line named in the argument, 

RET The PDP-8E abbreviation for the 
RETURN statement. The TRS-80 level 1 
and Palo Alto Tiny Basic use the same 
abbreviation followed by a full stop. 

RETURN The standard ANSI statement 
used to complete a GOSUB routine. 

RIGHT- A function which isolates a 
specified number of string characters 
starting from the right-most character. It is 
sometimes used with a **S*' appended. 

RND A standard ANSI function which 
returns a random number. Its use is non- 
standard in some Basics and details are 
given in Your Computer, August 1982, 
page 59. The statement RND (-X) when 
used on the Apple II is equivalent to 
RANDOM. 

RU An abbreviation for RUN. 

RUN A command which causes a computer 
to start executing the program resident in 
its memory. 



S. The TRS-80 level 1 and Palo Aito Tiny 
Basic abbreviation for STEP, 

SAVE A widely-used command which 
causes a program, resident in the memory, 
to be copied on to a cassette, or in some 
cases on to disc. 

SCRN A special function used on the Apple 
II which returns a value identifying the 
colour of a specified graphics block, 

SET The statement used in TRS-80 Micro- 
soft Basic which turns on a graphics block 
specified by its arguments. 

SGN A logical function which returns -1,0 
or +1 depending respectively on the 
argument being negative, zero or positive. 

SIN An ANSI standard function which 
returns the sine of its argument. The 
argument should usually be started in 
radians. 

SLEEP A statement used to cause the 
suspension of program execution for the 
number of tenths of a second specified by 
the argument. 




^'^S/C D/CT/o; 



SPACE A fiinction used to print a number 
of spaces in an output. The number being 
specified by the argument. Sometimes a $ 
is appended to this word. 

SPC Similar function to SPACE. In the case 
of the BBC Micro the number of spaces 
inserted is argument module 256. 

SQR The ANSI standard word for the 
function which returns the square root of a 
positive number. 

SQRT The same as SQR. 

ST An abbreviation for the STEP function. 

ST, The TRS-80 level 1 abbreviation for 
STOP. 

STEP A standard ANSI word used as part 
of a FOR . . TO . , STEP function which 
indicates the size of the increment by its 
argument which can usually be positive, 
negative, or non-integer. 

STO An abbreviation for STOP. 

STOP A statement which halts the 
execution of a program and puts the 
computer in the ready mode. A standard 
ANSI word. 

STRS A useful function which converts a 
numerical value into its string equivalent. 

STRINGS A function which prints a ASCII 
character a specific number of times. The 
character code and the number of repeats 
being the arguments. In some computers 
the actual character, in quotes, can be the 
argument. 

STUFF A statement used on Opus 1 and 2 
machines to place integer values between 
and 256 in specified memory addresses. 

SYS An abbreviation for SYSTEM. 

SYSTEM A command and a statement 
which places the computer into the 
monitor mode to handle machine-language 
programs directly. 



T. This abbreviation is used in TRS-80 level 
1 Basic to mean both THEN or TAB, The 
interpreter recognises the TAB meaning if 
it is followed by a numeral in parenthesis. 
For example, 

T.dO) 
means 

TAB 10 
and 

T.10 
means 

THEN 10 

TAB A standard ANSI word which is used 
in conjunction with PRINT statements, it 
causes the cursor, or printer carriage, to 
move to a position corresponding to the 
number used as an argument from the left- 
hand edge of the line. I 



I 



YOUR COMPUTER, MARCH 1 983 1 1 1 



R MIND FLY AWAY 





Due to the incredible demand for the Alpha Conuodrum Program, we are able to provide a £100 prize for ever>* month of its availability. Entries 

will be accepted for two more months leaving some eight weeks to solve the problem. All entries should also contain a brief description of an 

original idea for a future Conundrum, The entries which contain the correct solutions together with the most elegant idea for a future puzzle as 

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do not solve the problem in time. Entry solutions should be submitted on a postcard in a sealed envelope with your name and address clearly 

stated. These competitions are not open to employees of the company or to any person directly or indirectly associated vvith its activities. 

No correspondence can be entered into and tlie decisions of the company's Software Manager regarding all matters relating to these competitions 

will be final. Winners will be notified by po»t and entr>' implies acceptance of these rules. 

Only individual purchasers of programs w*UI he olig;ible to enter. 



©K13@/*\ S®l?t?M*\Sia 



Please send me an Alpha Conundrum Program for D ZX81 16K-£6.50 " Spectrum 16K.£6.50 D Vic 20-£6.50 D BBC B'£6.50 
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1 1 2 YOUR COMPUTER. MARCH 1 983 



RESPOMSe FHAME. 



Do you have a problem? Your manual is 
incomprehensible or you just cannot get the 
hang of that programming trick you tried — 
whatever it is, Tim Hartnell will do his best to 
answer your queries. Please include only one 
question per letter and mark them "Response 
Frame". 



SPLIT SCREEN 

■ ! wish to write a program on 
my Spectrum, part of which 
involves scrolling the top half of 
the screen up and down, and the 
top left-hand and right-hand 
quarters of the screen to left and 
right individually. Please could 
you explain how this could be 
done? 

Peter Ruiiy, 
Lutott, 

Bedfordshire, 
The easiest vcay lo do this is lo hold 
the contents of each segment of the 
screen in a long suing. You then 
print the string in segments> using 
Print At. For example, to prim the 
left-hand corner, you could use a 
sequence such as: 

PRINT AT 0,0; A${ TO 71; AT 1,0; A$(8 
TO 16); AT 2,0; A$ (17 TO 25) 
and so on. 

SOLDER JOY 

■Following the article in Your 
Computer on converting Atari 
joysticks for use on a Sinclair 
ZX-81f I would like to know if 
machine-code progt^ams which 
use the arrow keys for move- 
ment will automatically run 
using the joystick. Also, is it 
worth the trouble of soldering 
the chips, or would I be better ofT 
buying a ready*made Sinclair 
joystick? 

S Ray, 
Ipswich, 
Suffolk, 
Unfortun.^tely, machine pro- 
grams using the cursor keys will not 
automatically run using joystick. 
Programs have to be tailored very 
carefully to the actual joystick used. 
VtTicthcr or not is it worth making 
conversions for yourself, for joy- 
sticks or other peripherals, depends 
largely on your confidence in work- 
ing with electrical components. If 
you have any doubts, I would 
suggest you would be better off 
buying a unit ready-made, 

MOD TROUBLE 

■I have come across a program 
in a book which uses the Mod 
command. Could you tell me 
how to make this program run 
on my computer^ which does not 
have Mod? 

Martin James, 
Notiing Hilly 
London WIL 
David LIEK'S Basic Handbook y 
published by Compusoft, California, 
points out that the Mod command 
which prints the remainder of a 
division — Print 23 Mod 4 will give 
3, the remainder when 23 is divided 



by 4 — can be emulated as follows. 
The form of the command generally 
is X Mod Y. To make A equal to X 
Mod Y, when your computer does 
not have Mod, include the line 
A = iNTiViX/Yl) ^ ,001 
You will fmd that Lien's book is an 
invaluable aid when trying to 
convert programs from foreign 
Basics into the dialect used by your 
own computer. 

CAT PEOPLE 

■I have been the proud owner of 
a large ginger cat for over four 
months* I realise the limitations 
of my cat, but I was w*ondenng if 
you could help me with one 
particular problem. I also own a 
ZX-81 which has been damaged 
by my ginger cat, who pushed it 
off the edge of the table. The 
computer will now no longer 
load programs which 1 once 
taped, and if I try to save 
programs, there is a fluctuating 
whistle with a very much 
reduced program signal. I would 
be very grateful if you could tell 
me what the fault is, and how it 
can be corrected, 

F Floor, 
Hampton, 
Middlesex. 
1 Mi'ST admit I was not sure what 
you were going to ask when you 
started talking about your, cat, but 
once you mentioned the computer 
being knocked to the floor I realised 
the letter was not a joke, as I had at 
first feared- Despite all that, 1 am 
afraid I can not help you. Diagnosis 
of hardware faults by letter is a 
notoriously thankless task. I am 
afraid you will have to send your 
computer back to Sinclair Research 
for repair. It is very unlikely thai 
Sinclair will also be able to do 
something about your cat, 

PERICLES RULES 

■ I am waiting deliver^' of my 
BBC model A. In the meantime, 
I am writing some programs for 
it. I would be pleased if you 
could tell me if the following 
statement, in immediate mode, 
MODE 7, PRINT CHR$ 
(1301;*TERICLES";CHR$n32); 
"PERICLES" 

will ptnnt the name in two 
different colours? That is, is it* 
possible to have more than one 
foreground colour in the same 
line? 

P J IsahageaSf 

Attica, 

Greece. 

There is kg restriction on the use of 

different foreground colours on a 

single line mode 7 on the 6BC 



computer, except for the fact that 
each colour control character — that 
is, the CHRS(130) or whatever - 
takes up a single space, so a blank 
appears every time there is a control 
character. If blanks do not bother 
you, you could have the different 
letters of your name chosen 
randomly. The following program 
would do this. 

10 G0SU8 too 

20PRINT"P"::GOSUB 100 

30PRINrE";:GOSUB 100 

90 GOTO 10 

100 PRINT CHR$f128 * HNDiB)); 
110 RETURN 

TIME BOMB 

Recently I acquired a copy of a 
certain program from a friend. 
\^lien I list the program, there is 
a line 64 11 in between lines 877 
and 1010. It reads 

6411 cursor STRUCTIONS 
in inverse. When I min the pro- 
gram, and try and input 
something, I obtain error code 
C/641L I wonder if you could tell 
me why this happens — it runs 
on my friend^s computer* 

Stephen Richards, 
Billingshursty 
West Sussex. 
Ik the first place, copying 
commercial software is robbing the 
programmer of his or her royalties, 
so I am afraid I can have little 
sympathy for you if you have copied 
a program which your friend 
bought. It is quite possible that the 
company which made the software 
has set a time bomb such as you 
describe to stop illegal copies from 
running. The way to remove the odd 
line is to Poke the exact address 
where the line is held. Determining 
such an address is not easy to do. If 
the program you are copying is not a 
commercial program, it seems that 
either your computer has corrupted 
the program, or it was corrupted by 
your friend's computer when Saving 
it. Sometimes an electrical discharge, 
like an electrical appliance starting 
up in the house during the Saving 
process, can put a corrupting "blip" 
on the program, producing similar 
results to those you describe. 

KEY FEELINGS 

■ I am considetnng buying an 
Atari 400 computer because of 
the vast amount of software 
available for it. I was wondering 
if you could tell me of an easy 
way to put a real keyboard on 
the Atari when I receive it. 

Andrew Know, 
Edinburgh, 
First, i woi'i,i> suggest you do not 
judge the Atari 400 keyboard too 
harshly until you have tried it. After 
the frustration of working on 
membrane keyboards like the ZX-81, 
you could be forgiven for believeing 
the Atari 400 would also be 
annoying to program, but you may 
not find it so. I find the 400 a 
pleasant computer to work with, 
because the keys have little raised 
edges, which make for a much more 



positive feel than the smooth 
membrane keyboards like the ZX-81. 
As well as this, the keyboard gives a 
positive bleep every lime you hit a 
key, and this audio feedback makes 
typing easy. There is at least one 
company selling add* on keyboards 
for the 400, but I would work with 
the computer before deciding that 
one of these is vital. 

THE STORK TEST 

Is there any way of checking that 
my Sinclair Spectrum 48K is, in 
fact, a 48K model? There seems 
to be no external distinguishing 
feature to identify the two dif* 
ferent models* 

C Browning, 
Hampton, 
Middlesex, 
If you look through the hole in the 
back of the computer, where the 
Printer plugs in, you will see a 
number of circular brown objects on 
a 48K model. These are not present 
on the 16K version. If you enter 

DIM A${40.000) 
as a direct command on your 
computer, and you obtain an out-of- 
memory repon code, you have a 16K 
machine. 

SHOP AROUND 

■ As a new reader, in need of 
some advice, I wish to buy a 
home computer, mainly for 
good quality education and 
games program. I am contem* 
plating buying a Dragon 32, as it 
seems to have some good 
specification at a budget price. 
Could you tell me if I would be 
restricted to buying only the 
software supplied by the manu- 
facturer of the computer? I am 
very keen to buy some Acomsoft 
items> such as Snapper^ 
Monsters and Defender, and I 
need to know whether or not 
these would be compatible. Also, 
would I need to buy any 
accessories, such as a tape unit 
extended RAM, or whatever? 

P Wilson, 
Lancaster Road, 
London WIL 
Ai,THOUGH YOU are not restricted to 
software produced by the manu- 
facturer or distributor of the 
particular computer you buy, you 
arc restricted to software which is 
written for the computer which you 
have bought. Acorn software, 
whether for the Atom or the BBC 
Microcomputer, will not run on the 
Dragon, If you like this software so 
much, it may be well worth 
considering buying an Acorn 
computer. Unless you buy a disc 
unit for your computer — and many 
of the cheaper computers do not, as a 
rule, support discs — you will have 
to obtain a cassette tape player to be 
able to load software into your 
computer. Exceptions to this include 
the Texas TI-99/4A which accepts 
plug-in cartridges for programs. You 
cannot, however, save your own 
programs on to cartridges. A tape or 
disc unit is needed for this. | 



YOUR COMPUTER, MARCH 1 983 113 



ZX81 AND SPECTRUM 
HARDWARE 

ZX81 KEYBOARD 



FULLY BUILT! 




• Full size keyboard 

• Plug in — No soldering 

• Full Repeat on all keys 

• Single keys for RUBOUT, EDIT, FUNCTION and CURSORS 

• Large space and newline keys 

• 2 Shift keys. 

We also are stockist for Redditch Electronics. 
See their Ad in this issue and Feb 83 page 86. 
Our prices are 10% less for all their products. 

Metal case to hold our keyboard, RAM pack, ZX81, PSU and 
strong enough to put TV on top. £26. 

Postage 40p under €4, Export (surface} £2. 
Send SAE or 20p for catalogue. 
Cash with order or ACCESS. 

HARRIS a LOCKYER ASSOCIATES 

33 Pedmore Close, Woodrow South, 

Redditch, Worcs B97 7XB 



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SOFTWARE & 
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NETWORKING 

& EDUCATION 

SPECIALISTS 



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Pfeas« send your 
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121 DUDLEY ROAD, GRANTHAM, 
LINCS NG31 9AD Tel: (0476) 76994 . 



SPCCtAUSTS 




ffltm 



ZX Business Software. 

FOR SMALL BUSINESSES AND THE SELF EMPLOYED 

Business Bank Account: this program enables you to 
make debits under 1 1 subheadings. Statements include 
totals of all subheadings. £8.75 

Sales Day Book: for all your invoices, this program wilt 
enable you to prepare statements of outstanding 
invoices. Program will also calculate VAT, £8.75 

Purchase Day Book: keeps a complete record of all 
your purchases under 11 subheadings. The program 
will also calculate and deduct VAT, £8.75 

Quarterly Analysis: quarterly totals from Bank 
Account. Purchase and Sales programs can be 
analysed with this program. £4.75 

All the programs have full search facilities and will 
enable you to prepare quarterly accounts for your VAT 
returns and annual accounts for your accountant. 
These programs can also be used by companies not 
reg. for VAT. 

Business Pack: incl. Bank Account, Sales and 

Purchase programs. £25 

Please specify nnemory size when ordering for your 
ZX81 and ZX Spectrum. 

All prices include VAT, Post & Packaging. For details 
send S.A.E. to: 

TRANSFORM LTD., 
41 Keats Ho., Porchester Mead, Beckenham, Kent. 
Tel: 01-658 1661 



VIEWPOINT 



THE PROGRAM THAT 
YOUR ZX SPECTRUM HAS 
BEEN WAITING FOR' 



Draw complex 3-dimensional objects. View them after rota- 
tion in any or all of 3 dimensions. 
Features: 

1) Rotation in 3 dimensions about a single point. 
2} Rotation about a line between two points. 
3} Generation of :>tereo pairs 
4i View from one point towards another point. 

Objects can be stored separately on tape and copied to the ZX 
printer 

Written in BASIC for you to modify to your own require- 
ments. 
Ideal for computer modelling, molecular modelling, CAO etc 

Viewpoint - with full instruction and examples 
£6.50 

I Jusi siarting to write machine cocJe programs^ The ideal as- 
semfoler for beginners IS Uhravtolei. Look at the facifi!«es that Jt 

I offers: 

Works entirely m decsmai ino hex problems): all 280 in- 
structions correclly assembled; supports the pseudo 
instructions ECU. ORG tmuliipfe ORGs allowedJ, DEFB, OEFW 
and DEFS; code can be assembled at one location and then re- 
located; allows alphanumeric labels of any length: full listings 
of assembled code and mnemonics can be output to the 
printer; full error trapping with faulty instruction clearly indi- 
cated; comments can be included in the source file. 
The ideal complement to Ultraviolet 'S Infrared - an easy-to 
use disdssembter 
So now there is no need to be intimidated by machine code * 

I with Ultraviolet and Infrared its child's play' Buy them from 
the machme code spectaltsts - ACS Software 



ULTRAVIOLET £7.50 



INFRARED - £6.75 



All our Spectrum programs will work in both 16K and 48K 
models Please send sae for details of 2X81 programs. 



ACS SOFTWARE 7. Lidgelt Crescent. 
Roundhay, 
Leeds LS8 1HN 



1 14 YOUR COMPUTER, MARCH 1983 



FINGSJmK. 



Fingertips is our regular calculator column 
covering calculator news, programming hints 
and examples of unusual applications. The 
column is written and compiled by calculator 
enthusiast David Pringle who is glad to hear of 
any of your ideas. Your Computer pays £6 for 
each of your contributions published. 



The first program this month 
comes from Albert Ball of 
Warrington, for his CBM PR- 100. 
The program performs the basics of 
Boolean Algebra and h intriguing in 
being the first calculator program I 
have seen to do this. Boolean algebra 
refers to the logical combination of 
binar)^ codes and can be used in 
some up-market calculators. 
Applications of the work are seen 
not only in computing but digital 
electronics. 

The following sequences can be 
used 10 evaluate logical expressions. 
The two logical values arc assumed 
stored in Ml and i\i2 but any 
memories can of course be used. 



AND MR 1 X MR 2 



6 steps 



OR MR 1 4 MR 2 -^ X 



F INT 



9 steps 



INVERT MR 1 + /^ + 1 - 

6 steps 

EXCLUSIVE OR MR 1 ^ MR 2 
■r 2 X F FRAC 2 12 steps 

These sequences can be chained 
together, to compute results for more 
complex expressions. For example, 
the expression (A.B) + (c:,D) gives 
the following sequence: 
<A in MO. 8 in Ml, C in M2 and D in 



M3) MR Ox (MR 1 - / > 1> + tiMR 
2 ^ > * 1 xMR3) + / + 1* - s/'x 
FINTR S. 

A further program is useful for pre- 
setting memory contents prior to 
evaluating expressions when esiab* 
lishing truth tables. Memory 
contents can be set manually, of 
course, hut this becomes tedious if 
many variables are involved, or if 
many states have to be analysed as 
for truth tables. 

A decimal number is entered 
manually and the program runs as 
many times as there arc memories to 
be set. The effect is to load the 
memories to be set, in other words 
load the memories with binary digits 
corresponding to the decimal num- 
ber entered. The most significant 
digit is in .MO, the next in .Ml and so 
on for as many digits as arc needed 
— up to a maximum of nine. 

For example, to generate a truth 
table for the expression quoted 
earlier, enter the program shown in 
locations 0-21 inclusive, and enter 
the key sequence also shown earlier 
from location 22 onwards. 

Fnter — ihe first decimal 
number, Ctoio 00 then press R/S 
four times — allowing the program 
to stop l>etween presses. This loads 
MO to M3 inclusive with zeros. Run 
the expression ev^aluation program 
from 22, and the result is given. For 



the next value, enter I, Goto 00 
again press R/S four times. Now MO 
to M2 contain zeros and M3 
contains 1 . Run from 22 for the next 
result, continuing in this way up to 
decimal number 15 generates a truth 
table - 

DEC NO. A B C O RESULT 

(M0HM1)iM2HM3) 







1 

2 

3 

4 

5 

6 

7 

8 

9 

10 

11 

12 

13 

14 

15 






1 
1 
\ 
} 





1 
1 
1 
1 



1 


1 



1 



1 



1 



1 


1 



1 



The memory loading sequence 
shown uses a feature of the CBM 
PR- 100 which is not described in the 
manual, that is 

F X <> M F 9M 
This has the cftcct of cycling the 
contents of all memories. MO 
contents go to M I, M 1 to M2 and so 
on, M9 contents go into the x 
register — the display — and the x 
register contents go into MO. 
Memory Loading Program. 





D 


1 2 





^ 


M 


1 


2 





2 




R/S 


3 


M 


F 


4 


9 


XOM 


5 


F 


F 


6 


FRAC 


9M 


7 


X 


F 


8 


2 


INT 


9 




GOTO 



Area by CQ-ordinates pfogram for the T/57, 














LRN 


















STO 


60 


32 





GOTOl 




25 


51 1 





01 


00 




2nd 


LBC 


2 


26 


86 2 


R/S 


02 


81 




RCL 







27 


33 


STO 1 


03 


32 


1 


IHV 


SUM 


3 


23 


-34 3 


STO 2 


04 


32 


2 


RCL 


6 




29 


33 6 





85 


00 




INV 


SUM 


2 


30 


-34 2 


R/S 


06 


81 




RCL 


2 




31 


33 2 


STO 3 


07 


32 


3 


2ND 


SUM 


5 


32 


39 3 





08 


00 




RCL 


3 




33 


33 3 


R/S 


09 


81 




SUM 


7 




34 


34 7 


STO 4 


10 


32 


4 


INV 


SBR 




35 


-61 


2ND LBC 


1 11 


86 


1 


LBC 


4 




36 


86 4 





12 


00 




RCL 


1 




37 


33 1 


R/S 


13 


81 




STO 


6 




38 


32 6 


STO 5 


14 


32 


5 


SBR 


2 




39 


61 2 ■ 





15 


00 




2 






40 


02 


R/S 


16 


81 




2ND INV 


SUM 


7 


41 


-39 7 


STO 6 


17 


32 


6 









42 


00 


SBR 2 


18 


61 


2 


KOT 




43 


22 


RCL 4 


19 


33 


4 


2ND 


1X1 




44 


40 


STO 2 


20 


32 


2 


R/S 






45 


81 


RCL 5 


21 


33 


5 


RST 






46 


71 


STO 3 


22 


32 


3 








47 




RCL 6 


23 


33 


6 








43 




STO 4 


24 


32 


4 








49 





Bent Boiler up^ of Denmark, has a 
Jackpot program for the PC- 1 211 
that has kept his friends occupied for 
hours, he says. 

In Dcf mode you press Shift A. 
You are asked for an initial number 
between imd 1 — up to ten digits. 
Enter this, and you arc shown the 
wheels one by one, then the 
winnings and your total. On pres- 
sing Enter vou arc asked for Hold? 

010 ENTER 
means hold the middle wheel. li'you 
do not want to hold, just press Knter 
again and the next game is in play. 

You will not be asked ibr Hold 
after winning. Hold cannot be used 
in two succeeding plays. Every game 
costs you two coins — H in line 20 — 
and you can win from two to 40 
coins — G in line 60. 

The priority of the signs is from 
the lowest: 

/ * • . Y S 

If you want to proceed from the last 
game J rather than from scratch, start 
on Shift B next time you turn the 
computer on. About the program: 
line 5 and sub- routine lines 190-220 
generate the first random number. 
The random generator — lines 
200-220 — is to be t'ound in Response 
Frame, March 1982. 

Lines 22 to 55 calculate the next 
random numbers, pick the corres- 
ponding sign, and show the wheels. 
Line 60 calculates the winnings — 
this can be adjusted by changing the 
traction 8/7. Lines 70 and 90 beep 1 
for every two coins you win and 
print the three wheels, your 
w^innings and your total numl>cr of 
coins J plus or minus. Lines 100 to 
170 handle the Hold function 
together with lines 250 and 260 and» 
to be specific, lines 24 and 26. 

For space in the listing I have used 
a dot. 'rwo dots mean two spaces. 

Jackpot program for PC 1277 

5 "A" H = 0: GOSUB 190 
10 "B" A$-'V": B$ '.": C$ "": 

W-0 
20 'X"H-H 2 
22 FOR X 1 TO 3 
24 IF A$(X* = "." GOTO 28 
26 GOTO 55 
28 GOSUB 200 
30 MX^ 11) J 
35 GOTO (J +41) 



"'" GOTO 50 
" " GOTO 50 
'• t " GOTO 50 

GOTO 50 

" - " GOTO 50 
'•|i GOTO 50 
■Y" GOTO 50 
"$" GOTO 50 
': A$: e$; C$ 



41 A$(Xh 

42 A$ (XI 

43 k% tXi 

44 A$ (X» 

45 AS (XL 

46 A$ iX> 

47 AS IX» 

48 AS (X) 
50 PAUSE ' 
55 NEXT X 

60 G INT((L M)'(M N)' 

(6+M-2)^(iL m^m^ my 

(24M'8/7)» 
70 H H + G: BEEP G/2 
90 PRINT "...."; AS; BS; C$; ",./'; 

G; "..TOT./'; H 
100 IF WOO LET W: 0: GOTO "8" 
110 IF G GOTO "B" 
115 K 

120 INPUr\.HOLD.>.(0 1)."; K 
125 W K: IF K GOTO "B" 
130 FOR X 3 TO 1 STEP I 
140 GOSUB 250 
150 IF P^OLET A$(X)-"/' 

(coniinued on next page} 



YOUR COMPUTER. MARCH 1983 115 



HMGSWPS. 



(continued from previous page! 

160 NEXT X 

170 OOTO "C" 

190 INPUT "INIT.. NUMBER. 

<0.TOJ)/';P:H=iP*2J/2 
200 -(2 + nni5 

210 z^zmiz 

220 J = INT(Z*8): RETURN 
250 P = K-iNT(K/10)-10 
260 K = INT(K/10>: RETURN 

Mark Vince of Halesowen has 
wriaen an intriguing little program 
which will output exactly the 
factorial of any number between 1! 
and 237*. I await the flood of letters 
informing me of a quicker method. 
Mark usc$ a Casio fx-602P. 

This program calculates all digits 
of n! for any n between 1 and 237. 
The program calculates all digits and 
displays the first few digits; 
successive presses of Exe then 
display blocks of seven digits at a 
time. When all digits arc exhausted 
the letter E is displayed to signify 
End. Long execution times must be 
expected for large values of n. 

Finally a program for the TI-57 
from B Maddocks of ShcfTield, It 
will calculate the area of any 



polygonal shape — a great improve- 
ment on Simpson's Rule. This 
program will give the area of any 
shape or cross-section from the co- 
ordinates of that shape based on; 
V--\N(Xi=XiHY,i + i,-Y(Hn) 



' ^,.2 


2 




When Yrt+ 1 = 71 






See figure L 




DISPLAY 


PRESS 


RST 





#♦ 


4 


4 


,j 


fl/S 







3 


3 




R/S 


a 


,, 


1 


t 


,, 


'/- 


-1 


,, 


R/S 





tt 


2 


2 


** 


+ /- 


-2 


■« 


R/S 





,, 


3 


3 


J, 


+ ;- 


3 


• f 


ft/S 





♦* 


2 


2 


„ 


♦ /- 


-2 


„ 


R/S 





f * 


5 


5 


», 


R/S 





*f 


SBR4 


33 



Mark Vmce's factorial program. 

MODE. 67 HODE 2 

PO^if:-" MflC+/-MIH00 1 mmi f1IK3F 7 la niN IF 

LBLO 1 rtlN 4F OMINF LBL5 0riIH2F 

LBLl 1 n*¥ IND tIRF X MROO*-/- ♦ MR^F = IND MI*^ - MRlF«x>0 

GOTO 2 GOTO 3 

LBL2 IND rf5rF - miF - INT NIN 2F=x«ftlF=IND MINF GOTO 1 

LBL3 HRF-MR4F=x 0H+4F MR4F-MR3F-X GOTO 4 GOTO 5 

LBL4 N+3F IS2 GOTO0 MR3F MIH m IHD MR0© LOG [NT MIN IF 

LBL6 IHD fIRee MRIF 16 FRRC IND MIN m - ".*•' MRIF 10 x INB 

MR00-IND MINee 1 M-IF MftlF X 9 GOTO 6 6 MINIF ";" HLT'" DSZ 

G0T06 *•£" 



figure f. Area by coordinates 

X2Y2 




X1Y1 


/2 

X3Y3\ 


A 


\ 

i\ 

\ 
\ 
\ 
\ 
\ 

n> 

/Xn Yn 


\4 




5/ 


X4Y4 




X5Y5 


Figure 2. Foihw coordinates clockwise i 

3,-1 


?r anti- clockwise 

4,3 


/■ 




■\ 


/ 




\ 


-2-3 




-2,5 , 



The Cheapest Known Rampacks In The World 



I6K RAMPACKI 
£19.75 



FULLY COMPATIBLE WITH ZX81 AND ALL 
ACCESSORIES -SIMPLY PLUG STRAIGHT 
INTO USER PORT AT REAR OF COMPUTER 



Fully cased tested and guaranteed 

Gold plated edge connector coated for extra 
long life 

Secure no wobble design 

Same sleek case size for both versions 




64K RAMPACK 
£44.75 



PRICE INCLUDES VAT & P&Pdelivery normally i4 days 

Send cheque/ P.O. payable to: 

CHEETAH MARKETING LTD. 

359, The Strand, London WC2. Tel: 01-240 7939 



ne YOUR COMPUTER, MARCH 1083 



Sinclair ZX Specti 



16Kor48KRAM... 
full-size moving- 
key keyboard., 
colour and sound, 
high-resolution 
graphics... 

From only 

£125! 



I ZX Spectrum 



ontm CYAN 



OEF f N J^M 



CLOSE*! 



YELLOW WH1 



MOVE E^ 



RESTORE DATA^ 



i<;t B»N 



First, there was the world-beating 
SinclairZXSO. The first personal computer 
for under £100. 

Then, the ZX81. With up to 16K RAM 
available, and the ZX Printer. Giving more 
power and more flexibility. Together, 
they've sold over 500,000 so far, to make 
Sinclair world leaders in personal 
computing. And the ZX81 remains the 
ideal low-cost introduction to computing. 

Now there's the ZX Spectrum! With 
up to 48K of RAM. A full-size moving-key 
keyboard. Vivid colour and sound. High- 
resolution graphics. And a low price that's 
unrivalled. 

Professional power- 
personal computer price! 

The ZX Spectrum incorporates all 
the proven features of the ZX81 . But its 
new 1 6K BASIC ROM dramatically 
increases your computing power. 

You have access to a range of 8 
colours for foreground, background and 
border, together with a sound generator 
and high-resolution graphics. 

You have the facility to support 
separate data files. 

You have a choice of storage capa- 
cities (governed by the amount of RAM). 
16K of RAM (which you can uprate later 
to 48K of RAM) or a massive 48K of RAM. 

Yet the price of the Spectrum 16K 
is an amazing £125! Even the popular 
48K version costs only £175! 

You may decide to begin with the 
16K version. If so, you can still return it later 
for an upgrade. The cost? Around £60. 



Ready to use today, 
easy to expand tomorrow 

Your ZX Spectrum comes with a mains 
adaptor and all the necessary leads to 
connect to most cassette recorders 
and TVs (colour or black and white). 

Employing Sinclair BASIC (now used 
in over 500,000 computers worldwide) 
the ZX Spectrum comes complete with 
two manuals which together represent a 
detailed course in BASIC programming. 
Whether you're a beginner or a competent 
programmer, you'll find them both of im- 
mense help. Depending on your computer 
experience, youMI quickly be moving 
into the colourful world of ZX Spectrum 
professional-level computing. 

There's no need to stop there. The 
ZX Printer-available now- is fully 
compatible with the ZX Spectrum, And 
later this year there will be Microdrives for 
massive amounts of extra on-line storage, 
plus an RS232 /network interface board. 




Key features of the 
Sinclair ZX Spectrum 

• Full colour- 8 colours each for 
foreground, background and border, 
plus flashing and brightness-intensity 
control 

• Sound - BEEP command with variable 
pitch and duration. 

• Massive RAM - 16K or 48K. 

• Full-size moving-key keyboard- all 
keys at normal typewriter pitch, with 
repeat facility on each key. 

• High-resolution -256 dots 
horizontally x 192 vertically, each 
individually addressable for true high- 
resolution graphics. 

• ASCII character set -with upper- and 
lower-case characters. 

• Teletext-compatible -user software 
can generate 40 characters per line 
or other settings, 

• Highspeed LOAD &SAVE-16Kin 100 
seconds via cassette, with VERIFY & 
MERGE for programs and separate 
data files, 

• Sinclair 16K extended BASIC - 
incorporating unique *one-touch' 
keyword entry, syntax check, and 
report codes. 



um 




ZX Spectrum software on 
cassettes -available now 

The Spectrum software library is 
growing every day. Subjects include 
games, education, and business/ 
household management. Flight 
Simulation, ..Chess, ..Planetoids... 
History...lnventions...VU-CALC...VU-3D 
...Club Record Controller.. .there is 
something foreveryone.And they all 
make full use of the Spectrum's colour, 
sound* and graphics capabilities. You'll 
receive a detailed catalogue with your 
Spectrum. 

ZX Expansion Module 

This module incorporates the three 
functions of Microdrive controller, local 
area network, and RS232 interface. 
Connect it to your Spectrum and you can 
control up to eight Microdrives, 
communicate with other computers, and 
drive a wide range of printers. 

The potential is enormous, and the 
module will be available in the early part 
of 1983 for around £30. 



iincil 



Sinclair Research Ltd, Stanhope Road^ 
Camberley, Surrey GU15 3PS. 
Tel: Camberley (0276) 685311, 



TheZXPrinter-^ 
available now 

Designed exclusively for use with the 
Sinclair ZX range of computers, the 
printer offers ZX Spectrum owners the full 
ASCII character set -including lower-case 
characters and high-resolution graphics. 

A special feature is COPY which 
prints out exactly what is on the whole TV 
screen without the need for further 
instructions. Printing speed is 50 charac- 
ters per second, with 32 characters 
per line and 9 lines per vertical inch. 

The ZX Printer connects to the rear of 
your ZX Spectrum. A roll of paper (65ft 
long and 4in wide) is supplied, along with 
full instructions. Further supplies of paper 
are available in packs of five rolls. 



The ZX Microdrive- 
coming soon 

The newMicrodrives, designed 
especially for the ZX Spectrum, are set to 
change the face of personal computing 
by providing mass on-line storage. 

Each Microdrive can hold up to 100K 
bytes using a single interchangeable 
storage medium. 

The transfer rate is 16K bytes per 
second, with an average access time of 
3.5 seconds. And you1l be able to connect 
up to 8 Microdrives to your Spectrum via 
theZX Expansion Module. 

A remarkable breakthrough at a 
remarkable price. The Microdrives will be 
available in the eariy part of 1983 for 
around £50. 




How to order your ZX Spectrum 



BY PHONE-Access.Barclaycardor 
Trustcard holders can call 01-200 0200 for 
personal attention 24 hours a day, every 
day. BY FREEPOST- use the no-stamp 
needed coupon below. You can pay by 
cheque, postal order, Barclaycard. 



Access or Trustcard. 

EITHER WAY- please allow up to 28 
days for delivery. And there's a 14-day 
money-back option, of course. We want 
you to be satisfied beyond doubt - and we 
have no doubt that you will be. 



To: Sinclair Research, FREEPOST, Camberley, Surrey, GUIS 3BR. 


Order 


Qty Item 


Code 


Item Price 
£ 


Total 
£ 


Sinclair ZXSpectrum-16K RAM version 


100 


125.00 




Sinclair ZX Spectrum -48K RAM version 


101 


175.00 




Sinclair ZX Printer 


27 


59.95 




Printer paper (pack of 5 rolls) 


16 


11.95 




Postage and packing: orders under £100 


28 


2.95 




orders over £100 


29 


4.95 





Total £ 

Please tick if you require a VAT receipt D 

*l enclose a cheque/postal order payable to Sinclair Research Ltd for £ 
*Rease charge to my Access/Barclay card/Trustcard account no, 
*Please delete/complete | | [ | | | | 



as applicable 
I Signature 



i 



PLEASE PRINT 
[Name: Mr/Mrs/Miss 



I I I I 1 I I ' I t I I I I 1 ' 1 I I I 



lAddress i i i I I I I I t I I I I I I I I I I I I I I 



1 



I I I 1 I I I I 1 ' I I I I I I I I 1 ' I I I I 



I I I I I 1 1 I I I 1 ' I I 'II iV0C903l 



FREEPOST- no stamp needed. Prices apply to UK onty. Export prices on applicat 



ion. I 



Sinclair ZX Spectrum-technical data. 



DimensJons 

Width 233 mm 

Depth 144 mm 

Height 30 mm 

CPU/ memory 

Z80A microprocessor running at 3.5 MHz. 
16K-byteR0M containing BASIC interpreter and 
operating system. 

1 6K-byte RAM ( plus optional 32K-byte RAM on 
internal expansion board* or 48K -byte RAM. 

Keyboard 

40-moving-key keyboard with full upper and 
lower case with capitals lock feature. All BASIC 
words obtained by single keys, plus 1 6 graph ics 
characters, 22 colour control codes, and 21 user- 
definable graphics characters. All keys have auto 
repeat 

Display 

Memory-mapped display o* 256 pixels x 
192 pixels; plus one attributes byte per character 
sQuare, defining one of eight foreground colours, 
one of eight background colours, normal or extra 
brightness and flashing or steady Screen border 
colour also settable to one of eight colours. Will 
drive a PAL UHF colour TV set. or black and white 
set (which will give a scale of grey) , on channel 36. 

Sound 

Internal loudspeaker can be operated over 
more th an 1 octaves (actually 1 30 semitones) via 
basic BEEP command. Jack sockets at the rear of 
computer allow connections to external amplifier/ 
speaker 

Graphics 

Point, line, circle and arc drawing commands 
in high -resolution graphics. 
16 pre-defined graphics characters plus 21 user- 
definable graphics characters. Also functions to 
yield character at a given position, attribute at a 
given position (colours, brightness and flash) and 
whether a given pixel is set. Text may be written on 
the screen on 24 lines of 32 characters. Text and 
graphics may be freely mixed. 

Colours 

Foreground and background colours, bright- 
ness and flashing are set by BASIC INK. PAPER, 
BRIGHT and FLASH commands. OVER may also 
be set, which performs an exclusive-or operation 
to overwrite any printing or plotting that is already 
on the screen. INVERSE will give inverse video 
printing. These six commands may be set globally 
to cover all furl her PRINT. PLOT. DRAW orCIRCLE 
commands, or locally within these commands to 
cover only the results of that command. They may 
also be set locally to cover text printed by an 
INPUT statement. Colour-control codes, which 
may be accessed from the keyboard, may be 
inserted into text or program listing, and when 
displ^ed will override the globally set colours 
until another control code is encountered. Bright- 
ness and flashing codes may be inserted into 
program or text, similarly Colour-control codes in 
a program listing have no effect on its execution. 
Border colour is set by a BORDER command The 
eight colours available are black, blue, red, 



magenta, green, cyan, yellow and white. All eight 
colours may be present on the screen at once, 
with some areas flashing and others steady, and 
any area may be highlighted extra bright. 

Screen 

The screen is divided into two sections. The 
top section - normally the first 22 lines - displays 
the program listing or the results of program or 
command execution. The bottom section - 
normally the last 2 lines - shows the command or 
program line currently being entered, or the 
program line currently being edited. It also shows 
the report messages Full editing facilities of 
cursor left, cursor hght insert and delete (with 
auto-repeat facility) are available over this line. 
The bottom section will expand to accept a 
current line of up to 22 lines. 

Mathematical operations and functions 

Arithmetic operations of +. -, X, -^.and raise 
to a power Mathematical functions of sine, 
cosine, tangent and their inverses; natural logs 
and exponentials; sign function, absolute value 
function, and integer function; square root 
function, random number generator, and pi. 

Numbers are stored as five bytes of floating 
point binary - giving a range of +3 XI 0*^^ to 
+7X10^® accurate to 9^ 2 decimal digits. 

Binar/ numbers may be entered directly with 
theBINfunction.— ,>,<.>-.<— and maybe 
used to compare string or arithmetic values or 
variables to yield (false) or 1 (true) . Logical 
opejatorsAND.OR and NOT yield boolean results 
but will accept (false) and any number (true). 

User-definable functions are defined using 
DEF FN. and called using FN. They may take up to 
26 numeric and 26 string arguments, and may 
yield string or numeric results. 

There is a full DATA mechanism, using the 
commands RE AD, DATA and RESTORE. 

A real-lime clock is obtainable. 

String operations and functions 

Stnngs can be concatenated with +. String 
variables or values may be compared with —,>.<, 
>— , <— , <> to give boolean results. String func- 
tions are VAL. VAL$. STRS and LEN. CHRS and 
CODE convert numbers to characters and vice 
versa, using the ASCII code. 

A very powerful string slicing mechanism 
exists, using the form aS (xTO y). 

Variabte nannes 

Numeric - any string starting with a letter 
(upper and lower case are not distinguished 
between, and spaces are ignored). 
String -AS toZ$- 
FOR-^JEXT loops -A-2, 
Numeric arrays - A-Z. 
String arrays - AS toZS. 

Simple variables and arrays with the same 
name are allowed and distinguished between. 

Arrays 

Arrays may be multi-dimensional, with sub- 
scripts starling at 1 . String arrays, technically 
character arrays, may have their last subscript 
omitted, yielding a string. 



Expression evaluator 

A full expression evaluator is called during 
program execution whenever an expression, 
constant or variable is encountered. This allows 
th e use of expressions as arguments to GOTO, 
GOSUB.etc. 

It also operates on commands allowing the 
ZX Spectrum to operate as a calculator 

Cassette Interface 

TheZX Spectrum incorporates an advanced 
cassette interface, A tone leader is recorded 
before the information to overcome the automatic 
recording level fluctuations of some tape 
recorders, and a Schmitt trigger is used to remove 
noise on playback. 

All saved information is started with a header 
containing information as to its type, title, length 
and address information. Program, screens, 
blocks of memory, string and character arrays 
may all be saved separately. 

Programs, blocks of memory and arrays 
may be verified after saving to confirm successful 
saving. 

Programs and arrays may be merged from 
tape to combine them with the existing contents 
of memory. Where two line numbers or variables 
names coincide, the old one is overwritten. 

Programs may l>e saved with a line number, 
where execution will start immediately on loading. 

The cassette interface runs at 1 500 baud, 
through two 3,5 mm jack plugs. 

Expansion port 

This has the full data, address and control 
busses from the Z80A, and is used to interface to 
theZX Printer. theRS232and NET interfaces and 
theZXMicrodrives. 

IN and OUT commands give the I/O port 
equivalents of PEEK and POKE. 

ZX81 compatibility 

ZX81 BASIC is essentiallya subset Of 
ZX Spectrum BASIC. The differences are as 
follows. 

FAST and SLOW: theZX Spectrum operates at 
the speed of the ZX81 in FAST mode with the 
steady display of SLOW mode, and does not 
include these commands. 

SCROLL: theZX Spectrum scrolls automatic- 
ally, asking the operator "scroll?" e\fer^ time a 
screen is filled. 

UNPLOT: the ZX Spectrum can unplot a pixel 
using PLOT OVER, and thus achieves unplot. 

Character set: the ZX Spectrum uses the 
ASCII character set, as opposed to the ZX81 
non-standard set. 

ZX81 programs may be typed into the 
2IX Spectrum with ver/ little change, but may 
of course now be considerably improved. The 
ZX Spectrum is fully compatible with t he 
ZX Printer, which can now print out a full upper and 
lowercase character set. and the high resolution 
graphics; using LLIST LPRINT and COPY. 
ZX81 software cassettes and theZX 1 6K RAM 
pack will not operate with the ZX Spectrum. 





im=r 

ZX Spectrum 

Sinclair Research Ltd, Stanhope Road, Camberley, Surrey, GUIS 3PS. Tei: Camberley (0276) 685311. 




son\im£fH£. 



2^jy 



Software File gives you the opportunity to have your programs, 
ideas and discoveries published. We will accept contributions for 
any home computer provided they are submitted to Your Computer 
exclusively. Please double-check your programs and specify the 
memory they require before sending them, preferably on cassette. 
We pay between £6 and £36 for contributions published. 

Ti irk\r\ ^^ enter the program^ first type in a Rem 

I U I UU statement containing 305 characters, made up 

of nine full lines plus 17, as the first line of the 
program. If you then use the direct command 
Poke 16510,0. This will give the first line a 
line number of 0, so that you cannot 
accidentally erase it. Next type in and run this 
now well-known hexadecimal loader: 
1 REM . . .306 characters. . . 
10 LET X- 16524 
20 LET A$-"" 

30 IF A$ - A"" THEN INPUT A$ 
40 SCROLL 
50 PRINT X,A$iTO 2) 

60 POKE XJ6X0DE A$-CODE A$12> 476 
70 LET X X ♦ 1 
a) LET AS A$(3T0I 



David Green, 
Ashford, 
Kent. 

Here rs a machine-code arcade-type game 
written for the 16K ZX-81 . It will not work on 
a computer will less than 3.5K as the down- 
scroll routine, adapted from iMunir Zaman's 
program in the January 1983 Your Computer, 
crashes if used with a minimum display file. 
The game itself is relatively simple involving 
the player controlling a car driving along a 
road avoiding the edges of the road and any 
other cars, but the incredible speed of machine 
code makes it enjoyable and challenging. 



90 GOTO 30 

Notice that the actual program in machine 
code starts at 16524, the first 10 bytes being 
data. 

Enter ihe hexadecimal numbers shown in 
the machine-code listing: if you do not 
understand machine code, then these are 
numbers in base 16 which allow you to 
represent any number from lo 255 in just 
two digits — sec ihe Sinclair manual This 
loader allows you to enter as many codes as 
you like before pressing Xewline. If you think 
that you have made a mistake then type S and 
Xewline, and when the error report 3/50 
appears then type Let X = an address which 
you know is correct^ followed by Cioio 20, 

When you have entered the last code C9 ai 
16818 type S lo stop, and then enter the 
second Basic program which prints the 
instructions and activates the machine code. 
Save the resulting program on tape as any 
error in the machine code could c^usc a system 
crash and the loss of your program* 



Turbo: machine- code fisting 



16524: 

01 OB 00 

EO 43 84 40 

C5 

CDF5 08 

CI 

3EdO 

07 

AF 

D7 

D7 

D7 

07 

D7 

3E80 

07 

04 

78 

FE 16 

20 E9 

21 OE 15 

22 82 40 

21 00 05 

22 86 40 
2100T4 
22 88 40 

21 00 00 

22 8A40 

resTS: 

EO 4B 82 40 



r6e04: 
2A88 40 

3EEF 
OBFE 
F5 

CB47 
20 07 

7C 

FEOO 

20 01 

24 

Fl 

CB4F 

20 07 

24 

7C 

FE 15 

20 01 

25 

Z2 88 40 

16638: 

2A0C40 

01 84 02 

09 

E5 

012100 

09 

EB 

El 



7e 

FEOO 

C2 9F4t 

3E26 

07 

16686: 

EO 4B 84 40 

OC 

3A34 40 

CB47 

28 02 

OO 

00 

79 

FEFF 

20 01 

OC 

FE lA 

20 01 

00 

EO 43 84 40 

CO F5 08 

3E80 

07 

AF 

07 

07 

07 

07 

07 



EO 46 84 40 

89 

4F 

CO F5 08 

3E2D 

07 

16757: 

2A86 40 

EO 5B 88 40 

5A 

16 00 

2B 

7C 

85 

CA AF 41 

IB 

7A 

B3 

20 F5 

22 86 40 

W781: 

2A88 40 

2B 

7C 

65 

20 F8 

2A8A40 

23 

22 8A40 

C3C2 40 



3EF7 


0TB5 02 


3E80 


r6799: 


OBFE 


E0B8 


07 


0100 40 


CB6/ 


2A0C40 


16730: 


36 30 


20 01 


06 20 


3A34 40 


OB 


OD 


AF 


E6 07 


78 


3EEF 


23 


FE07 


36 BD 


D8FE 


77 


20 12 


Bl 


CB57 


10 FC 


3A35 40 


20 F7 


20 OT 


ED 46 82 40 £6 03 


01 FF FF 


OC 


CO F5 08 


3C 


C9 


EO 43 82 40 


2A0E4O 




rears: 

0100 00 
09 

end 16818 


Turbo: Basic fisting 






REM . 


- .(machine codeK . . 




10 CLS 








20 PRINT TAB 10;' 


TURBO";TAB 10; 



30 PRINT TAB 8:"fC>0. GREEN" 

40 PRINT 

50 PRINT "YOU HAVE TO DRtVE YOUR 

CAR ALONG THE ROAD AS FAR 
AS POSSIBLE IN A LIMITED 
AMOUNT OF TIME, AVOIDING 
THE ROADSIDES AND ANY 
OTHER CARS THAT YOU MAY 

60 PRINT 



70 PRINT "THE FASTER YOU 60. THE 

GREATER THE DISTANCE THAT 
YOU CAN TRAVEL IN THE TIME.' 
80 PRINT 

90 PRINT ''CONTROLS ARE:" 
100 PRINT "i5)-M0VE LEFT", "i8)-M0VE 

RIGHT", "(0) ACCELERATE", 

"(91 DECELERATE" 
110 FOR N 1 TO 200 
120 NEXT N 
130 PRINT AT 20.2; 

" PRESS ANY KEY TO START " 

(inverse video) 
140 PRINT AT 20.2;"PRESS ANY KEY TO 

START" 
150 IF INKEY$ "" THEN GOTO 130 
160 CLS 

170 LET X USR 16524 
180 IF X THEN PRINT AT 1,8;" YOU HAVE 

CRASHED" 
190 IF NOT X THEN PRINT AT 1,12;"T1ME 

UP" 
200 PRINT AT3.12;"SCORE:";PEEK 

16522 f 256* PEEK 16523 
210 IF INKEY$<^"" THEN GOTO 210 
220 IF INKEY$ "" THEN GOTO 220 
230 GOTO 160 
240 SAVE "TURBO" 
250 RUN 



Corridors of fear 



Cofin Carrutfrets, 

Edinburgfr, 



^^pwmm 



Thk THRHi-DIMEKSIOKAI. %'iew that confronts 
you when you play this game shows the 
corridors within a maze from which you must 
escape within a given time. Your current x-y 
co-ordinate is displayed along with your 
orientation and the x-y co-ordinate of the way 
out. 



iMovemeni around the maze is by means of 
the cursor control keys: 7 moves one space 
forward — unless there is a wall directly in 
front — and 5 and 8 turn the player through 
90*^ to the left or right. 

At the end of the game, a plan of the maze is 
drawn so the player can see where he took the 
wrong turning. The game consists of a short 
machine-code routine and a larger Basic 
program. 

The machine<ode routine clears the first 22 
columns of the display file and is best entered 
using the short Basic program. Run it, save it 
on tape and test the routine by typing 



LET X USR 23760 

Assuming all is well, delete lines 10-40 by 
typing their line numbers. Type in the main 
program, using: 

LIST 2 

instead of just IJst to avoid listing the 
niachine-codc. The graphics characters in line 
502i are graphic ABCII) and the inverse 
characters in 5786 say **Hit any key to being". 
Each maze used in random, generated from 
four out of eight possible segments, each tivc 
by five units giving a final maze of 10 by 10 
units. 



1 REH a^A^a^aAAa^^ata^a^^A^AA^ 

1© DfVTft 6 ^1-92^ 17^1©, ©^33. 0,6*,* 

ao ^OR KvssTee to 23-?ei 

3© RERD V: POKE X ,v 
4© NEXT X 
5>RRNDOHIZC : BORDER Oi PftPER 
INK 7 

10 CLS : pRx^r^ rt s^t^-^h r z c 



";RT lo.,a^**€'^ Colin c*rrulh«rs"; ?* 

PRINT RT SI, so 



so GO 5UB. SOOO 
A^ OD SU5 3000 
. d« I f ) 



S0 GO SUB iOOO 

60 LET ZS=INKEY« 

61 LET t=INT (<2e:i&*PEEK a^^^S* 
PECK 23672) - 50) 

63 INK 0! PLOT QA&,lime -I *B: D 
RRW 7,0; DRRU 0,1: DRRW *7,0: DR 
RU 0^1: DRRU 7,0' INK 7 

63 IF t^stintf THEN LET q*="TlH 
e UP ! '* : FOR e^lQ TO -15 *TEP -2 
: eCEP -i^e: NEXT *, GO TO 7000 

64. IF Z*c>"S" RND 3S*? '©" RNO 
Z><>"7" THEN GO TO 6© 

65 IF z*«*7*' THEN LET xpi=xp#-(X 

a RND »*(xp^yp> if ) c>'*i» ') 

66 IF xp>xmax OR xp t 1 THEN LET 
q^--*FRee !" GO TO 700© 



ev7 IF z$is*r^* THEN LET yF=yp^fy 

66 IF yp>ytt3x OR yp ^ 1 THEN LET 
^♦e-FPEE ! •' GO TO 700© 
70 IF z»B*S" THEN GO SUE dO0O 
60 IF z »«*•&" THEN GO ZUtt 4.100 
eS OO SUB 30©© PRINT RT ^1^23 

90 GO TO 50 
1000 i_ET XMXpi LET y-yp: LET dra 
Vaa000 

1015 GO 6US 300© 

401 SI LET ^ttUS'R 23760: »RINT RT 2 
1.9.: Xp; "> ''; yp 



(continued on next paget 



YOUR COMPUTER. MARCH 1983 121 



soFTim^mi. 



(continued from previous page^ 



lOaO IP tw^ tx ,y> { i } s"i^*' THEN CO S 

J© <irau GO TO X03O 

1032 IF m»(x,y) ti>3"e" THCN GO T 

O 103C^ 

103S IP US fx -9-»*tf #-xa> f r> = *iii'* THE 

N GO SUE^ ^i-^^ft-^CvO 

1030 ir KStx.y) «ri= w*^ THEN GO S 

UB dra*<if^l0; g6 TO 1©*© 

1©33 IF »»f^^y> *r>="«" TMCN GO T 

103S IF M^; fx #ya ^ V -XA> *r5a"W* THE 

N GO SUB draw ^4.0 

104.0 IF tt» (X .y) t ^ * w"!^** THEN GO » 

Ue <i i- 4» w +^0 : RfeTURN 

1045 IF n^Cv^yl Cf>s*'e*' THEN RCTU 

10S0 LET x-x+xa: LET y=y*ua. LET 
dr3ii» =dr3*» +10O: GO TO 1030 

S000 PLOT 0,175; DRAW 24 . -S* : DR 

f=>U 0^-127. DRRU -24.. -S^^: RETURN 

aoi0 PLOT 175^175; DRAU -S4 , -24. : 
DRRU 0> -IST. DRRU 24 ^ ^^4. : RETUR 

N 

~:02© PLOT S'4,151: DRRU 1S7,0 

1^021 DRRU 0^-137: DRRU -127^0 

S022 DRRU Pi,127 

5025 RETURN 

2030 PLOT 0.1S1: DRRU 24.»0: DRRU 
0.-127: DRRU -24 , & 

2035 RETURN 

2040 PLOT 175^ ISl DRRU -24-0: D 

RRU 0^-127; DRRU 24.0 RETURN 

2100 PLOT 24^151: DRRU 24^-24 D 
RRU 0^ -7«* DRRU -24 > «24 

2101 DRRU 0.127: RETURN 

2110 PLOT ISl.lSl: DRRU -24,-24: 

T>¥il=i)J 0^ -79: DRRU 24^ -24 
am DRRU 0,127; RETURN 
2120 PLOT 40.. 127: DRRU 79^0: DRR 
U 0^-79; DRRU -79^0, DRRU 0^79 
212S RETURN 

3 130 PLOT 24^127; DRRU 24^0 DRR 
U 0.-7CI: ORn\^ -24^0: RETURN 
2140 PLOT 1S1,127; DRRU -24.0: D 
?ifiU 0>-79: DRRU 24^© RETURN 
2200 PLOT 40.127: DRfiU le^-lC-; D 
RRU 0v -47: DRRU -1B^-1&: t^lkfiU ©^ 
79: RETURN 

2210 PLOT 127,127' £>RRiJ -16,-16: 
tfPifiU 0,-47: OPtfiU 16, -le: ^RfiU 
. 79 : RETURN 

2220 PLOT 64,111: DRRU 47,0 

2221 DRRU 0^-47 DRRU -47^0; DRA 
U .47 

222S RETURN 

2230 PLOT 4e,lll; DFtftU 16^0: URfi 
U 0,-47; r^RRi^ -16,® 

2231 RETURN 

2240 PLOT 127.111: OfifiU -16^0: D 

^f^U O - -47 Ofi^U 16.. 

?:?4 1 RETURN 

Ti?.00 Pi_OT 64,1X1 DfkftU 11. -11: D 

RRW 0.-2S: OftfiU* -11,-11: DRRU 0, 

4 7 RETURN 

2310 PLOT 111.111: DRRU -11,-11: 
DRRU 0,-2S; DRRU 11,-11: ORfiUi & 
.47: RETURN 

^320 PLOT 76,100: DRRU 26,0 DRR 
u 0,,-25i DRRU -25. G- DRRU 0,2S 
3 526 RETURN 

2330 PLOT 64,100: DRRU 11.0: DRA 
U 0.-26: DRRU -11,0: RETURN 
2340 PLOT 111,100: DRRU -11,0; D 
RftU 0^-26 Onhu 11,0; RETURN 
240© PLOT 76,100: DRRU 7,-7 DRR 
W 0, 11: DRRU -7,-7: DRRU 0,26: 
RETURN 

241© PLOT 100,10©: DRRU -7,-7: D 
RRU ©,-11: OFiR\S 7^-7: DRRU 0,25: 
RETURN 

2420 PLOT 62,93: OfkfiU 11, 0: DWRU 
0.-11: DRRU -11,0: DRRU ©,.11 

2421 RETURN 

2430 PLOT -P^,*^3: Ofkf^U 7^0: DRRU 

0,-11 DRRU '7,0: RCTURN 

2440 PLOT 100,93: DRRU -7,0: DRFl 

U 0.-11 DRRU 7,0: RETURN 

250© PLOT ©2.93: ORmJ 4.-4: I>Rf*U 

0^-3: DRRU -4,-4: DRRU 0,11 
2601 RETURN 



2510 PLOT 93.93: DRR^J -4.-4 DRfk 
U Of -3: DRRU 4,-4; ORRl>^ 0^11 

2511 RETURN 

2620 PLOT 66,69: DRRW 3.© t>P<f*U 
0^-3- DRRU -6.. G; DRRU D.. 3 

2621 RETURN 

263© PLOT 62, S9 DRRU 4,0 t>f!if^U 

0,-3: DRRU -4.0 RETURN 

2540 PLOT 5«3,©9 DRRU -4.0 DRRU 

0,-3: DRRU 4,0: RETURN 
7000 IF ya=l THEN LET r =1 : LET i 
«2; LET r .3 PETURN 

2fO20 IF y.'*»-l THEN LET f =4 LET 
L tt J- : LET p- =2 ; RETURN 

3030 IF K^mX THEN LET f =.2- i,eT I 
»1; LET f*4; RETURN 

3040 LET f»2r UET 1=4: LET i-«l: 
RETURN 
400© Xr ya = -l then let ya*^©: LET 

xa«l: RETURN 
402© IF ya=l THEN LET ya>0: LET 
>fa3-lt RETURN 

4030 IF xaal THEN LET xa=© LET 
ya»l RETURN 
*04O LET Xd«t0 LET y .»»>!; RETURN 

4 100 IF yj»ii~X THEN LET yaai©: LET 

v^w-i. PETLfRN 
412© IF_ya«l THEN LET ya»0: LET 
K a ml : RETURN 

4130 IF X3»l THEN LET X3»0 LET 
ya:=-l: RETURN 

4140 LET xas0; LET yd»l: RETURN 
600© DIH •*(10^1O,4). LET XliiX«l 
O' LET y»ax=10 
6O06 LEt d«3"t<>v" 

S010 POKE U6R "»'',2S6: POKE U6R 
*'d*'*7^26S 

6016 FOR X«l TO 7: POKE U6R "»"* 
X.0: POKE U&R "d'+X-l,0; NEXT X 
602© FOR x»0 TO 7: POKE USR "b' + 
X ,. 126 : POKE USR '' C " *-x . 1 NEXT x 
602S DIM 9**4>: LET «rf»'n L*' 
5100 PLOT 239,7: DRRU 9.0; DRRU 
0^161: DRRU --^,0: DRRU 6,-161 
520© FOR X«2© TO 1 STEP -1: PRIN 
T RT x,30; PRPER 4,** ", BEEP .©1 
a20-X: NE.NT .c 

6206 PRINT RT 20^2S,,- ** t i •€ " 
630© LET xa*l- LET y;* «© 
570© LET ysKl0: LET XS=1: LET Zm 
(RND> .49> 4-100: RESTORE 6O©0 ♦•z : G 
:? SUB 5S0O 

6710 LET x^=6; LET Z a: < RND ; . 49) f 1 
00: RESTORE 62©© 'hZ: GO SUB 6600 
672© LET ys»6: LET XS«1: LET Z^< 
RND>.49) «100; RESTORE 6400'^z: GO 

SUB SB00 
6730 LET X»M&. LET .z « iRND > • 43J *^1 
00: RESTORE 660© f-z: GO SUB 660© 
6736 LET z »RND 

S740 LET ye=l#Cz < *33j ^10*12 > .67) 
5745 IF NOT ye THEN LET yeelbfT ( 
RND*1©> ♦! 

676© IF ye=l OR y«Al0 THEN LET X 
ftaINT <RND*10)+1; GO TO 5770 
5760 LET xe=l+C9* (RND> .49) J 
5770 IF xa»l THEN LET O > ( x e , y «f > i 
21 -"e" GO TO 6760 
6772 IF xesio THEN LET a»txe,ye> 

f3J =••«": GO TO 5760 

S774 IF ye«l THEN LET ««(xft,ytt> ( 
4) = *e": GO TO 57©© 
6776 LET » > t xe , yc> I 1 > « **« " 
5765 LET yp=ll-ye: LET xp=ll-X« 
S7SS LET sx»xp: LET sygyp- BEEP 
^^^-i0_ip^iNT RT s 1 , X ; 'SatKBKtKB^ 

^jS^RRlUTfif 3 , 23 , *• EX IT *' , RT 4,3 
3 . '*mT " , PT S"- , 23^ .X « J " ^ " ; v« 
5790 LET ti»a»163: LET t w^Q : POKE 
23€3.74,. 0: POKE 23673^0: POKE 236 
72,0 

S795 PRINT RT 1,30; XHK 4; "»*' 
5799 RETURN 
6600 FOR y-ys TO y* -4 step -1 

5©1© RERD Z» 

562© FOR Xsl TO 5 

6630 LET »« (X «>x«-l,y I ^Z» r4Ji'X -^ T 

O 4 %.x J 

5640 NEXT X NEXT y 

5©60 RETURN 



Rocket command 



Gareth Rowland. 

Stockbridge, 

Sheffield. 



'iimd^mi 



Yor. A JXvr roughly in the screen ccnirc^ have 
to iry and proiccl all four cities at the bottom 
oflhe screen from incomiiig bombs from outer 
space. Each time one of the bombs hits a city, 
a dot appears underneath the foremost left 
city. When all cities have a dot underneath 
them, the game ends. To protect your cities 



you are equipped with a device which causes 
tile space-bombs to detonate prematurely. 
When you move the base and push the fire 
button an explosion will occur round your 
base. If a bomb is in the vicinity, it will stop- 
leaving its smoke trail, and another will appear 
at the top. 

To move your base, a joystick is required. 
The movement of the base is controlled 
between lines J40-410. The variables are 
Score for score, Base Ibr number of bases 
blown up, x,y and xl,yl for the btmibs and 
x2,y2 for your base. 



6©©© OVER 1 

6©a© FOR y=yai^x TO 1 STEP -1; FO 
R K«l TO x«ax FOR d«l TO 4 
6©3© IF B5tx,y> fd)=**5*'' THEN PRIN 
T RT 16-y ,x f^4, i9* (d) 
SO 36 NEXT d 

tj>0 3<S IF x«SX RND ywd^y THEN P'RINT 
^T 16-y ..y *4; " ***. c^O to 6£>4ei 

&0:i7 IF X iix-p RND ysyp r H^N F-RTNT 

^T IS-V , ^ +4^ <J* C f » 
a04© NEXT X . NE^ST ^ 
6©6© OUER © 
607© RETURN 

7CI00 IF q*(l^«"F** THEN BEEP .5,1 
BEE^ .5,16 
7O05 LET <i-USR a2F7e©. PRirTT RT 1 

<. INUEP^E 1,<1^ 

rois PRINT AT ir^a,** ^ ^X^i t pa 

^ * V i on*' 

r-OlS PRUSE 100 BEEP , a ^ -7 &EEP 

.4 *e 
7030 PRINT RT 31 ^ 0^ "Rno tKc r GO -^ 

iY^N^ " 
70^0 IF INKE^Ss-n" OR INKEYS*"N' 

THEN &TOP 

A3^ IF TNKEVS»"y*' OR XNKEY»«"V ' 

-r>4eK» HON 
"i?^.iO <iC' TG 'OtO 

S0O0 
3010 

S03O 

e04O 

0050 

ei00 
due 
di2o 

Cr 130 
Oi40 
A200 

aai0 
saa0 

5240 
&300 

63 lO 
S320 
©330 

e400 

64 10 
3430 
6430 
6440 
$S00 
8S10 
8520 
a530 
6540 
8S0O 
&ei0 

&ea0 

»&30 

I3d40 

e700 

S710 
a720 
S730 
€>740 

\ 



>DRTR "mm m mumm> mv ii« mm 

DRTR '* mm mm mm m mtt* 

DRTR "' t0 mm m m m t^ m ' 

DRTR "i^v m m m mm w 

DRTA " v«# vw If mm m ^ #' 

DRTR ''WMtf Mw mm « tin m* 

DRTR *' V «v If m mm mw m * 

DRTR *'VM •»»«•# m m ^t^' 

DRTR '* M <i n^ WW mm mm m 

rRTR ** mm m m je^m m mm 

DPTR *'m mm m mm m mm mm' 

DRTR "WW WW wwv WW* 

DRTR "WW WW w WW WW 

DRTR "WW WW wif m ww* 

DRTR " m WW WW w WW mm * 

DRTR **W WW WWWW W WW w 

DRTR **ww w vw WW «w 

DRTR " WW t^ WW w WW ww* 

DRTR " WW www WW w ww ww* 

DRTR " m mm m mm www' 

DRTR " W WW WW W WWWWWW * 

DRTR "WW W WW W WW W W 
DRTR WW WW WWW w 

DRTR ** w w WW WW WW www* 

DRTA ''WW WW W W WW W* 

DRTR *' WW WW WW W W WW WW 

DRTR *' WW WW w WW w w* 

DRTA ''WW WW WW w WW w * 

DRTR 'Vww WW w w w ww' 

DRTR " w WW w WW WW w* 

DATA *' www w WW w WW WW 

OflTA "w WW w WW WW ww; 

DRTA "WW w w w WW www 

Dfim *'ww WW WW WW «•»_. 

DATA *' WW W WW WW W WW 

DRTA "WW WW www 

DRTA ^^fc* m t0m m w ww vmm 

DATA " WW www W « U'^ WW 

DATA " WW WW WW W • 

DATA "w m mm mm mm m WW* 



y 



y 



N 



\ 



ex XT 
AT 

Sri. 



I 



©,!S 



\ , ^'"* 



The program takes only 1>922 byies so you 
can always modify iL Note: if you wish to Save 
it or Load it, you must first press the reset 
button. 

25 IF l>9 0R Kl THEN RUN 
115 DRAW ''C8;BMlia255:E10;F10" 
550 FOR R t TO M 2 

555 LINEi130J50) (x2.y2KPSET 

556 UNEtt30J50) <x2.y2KPRESET 
560 CIRCLE (x2,y2».R,7 

570 NEXT R 

575 (F PPOINT ix,y) 7 THEN SCORE 

SCORE ^ 5. 
RENUM. 



10 REM MISSILE COMMRND BY GRRETH 


ROWLRND..e JRN. 


20 CLS2 = PR I Hies .. " M I SS I LE COMMRHD ' 


' .: = PR I NTe40 .. " **•*:*:*****:*:*:+::*::+:* '• ; 


: PR I NT© 192.. "LEVEL 




OF DIFFICULTYCl TO lO)".;: INPUT I 


110 L I NEC 2 1 2 .. 1 50 >-< 220 .. 1 54 > .. PSET .. BF 


30 FOR D==l TO 100 = SOUND D.. 1=NEKT 


D 1 20 L I NE<: 1.-156 >-< 249 .. 1 65 > . PSET .. BF 


40 PMODE 3.1' SCREEN 1 .. 1 = PCLS 


130 X=RNCK251 > = Y=0 


50 BRSE=0 = SCORE-35 


140 :«;i~RND'::251 ::' = Y1=0 


60 F==33 ■• G:=0 •• T:^ 1 28 = Q==0 


150 K2=100=Y2=100 


70 PCLS 


160 E=*RND '::144> = R=^RND'::2) 


S0 L I NE'' 40 . 1 50 ::-< 48 .. 1 54 > . PSET .. BF 


170 POKE a;HFFD7..0 


90 L I NE< S 1 . 1 50 > -< S9 .. 1 54 > .. PSET .. BF 180 Y 1 =^Y 1 + 1 = X 1 =)< 1 -2 = Y= Y+ 1 ■■ X=X+ 1 


1 00 L I NE-r. 164.. 1 50 ::-< 1 72 .. 1 54 ) .. PSET .. 


BF 190 IF SCORE >30 THEN 200 ELSE 220 



17'^ YOUR COMPUTER, MARCH 1983 



SOFTW/OfSmE. 



£00 F-F+1 :G=G+3 
£10 PSET<F..G..6> 



££0 PSET 



..6:i = PSET<Xl..Y1..6;:' 



£30 IF SCORE >60 THEN £40 ELSE£60 
£40 T-T+1 =Q~Q+4 
250 PSE1<1,Q,S> 



£60 

£^ I L^ 

£80 
290 
300 
310 
320 
330 



IF Y=151 OR Yl=151 THEN 60 

IF XK4 THEN K1=X1 +2 

IF G=150 THEN BFlSE=BfiSE+l 

IF G-153 THEN 60 

IF Q=148 THEN BRSE-BRSE+1 

IF Q=152 THEN 60 

IF n=l THEN Xl=Xl+2 

IF R=2 THEN X-X-2 

340 J= JOYSTK-:: > = JJ= JOYSTK':: 1 > 

350 PRESEKX2..Y2::' 

360 P=PEEK'r 65280 ::• 

370 PRESET< F .. G > •• PRESET-T T .. Q > 

3S0 IF.J<10 THEN 






390 IFJ>50 THEN X£«>--;£+3 

400 IF JJ>50 THEN Y£==Y2+3 

410 IF JJ<10 THEN Y£-Y2-3 

420 IF Y2=>145 THEN Y2='Y2~3 

430 IF )<Z-<3 THEN ?<£^X2+3 

440 IF X2=3 THEN PSET':X2.. Y2.. 5 > 

450 IF Y2=^145 THEN PSETC X2. Y2. 5 > 

460 IF Y£*<3 THEN Y2=Y£+3 

470 IF Y2=3 THEN PSET< X2.. Y2.. 5 > 

480 PSET'::X£..Y2..7> 

490 IF BRSE>=1 THEN PSET<. 44.. 174.. 7 > 

500 IF BRSE >-£ THEN PSET< 35.. 174.. 7 

510 IF BRSE >=3 THEN PSETC 168.. 174. 

520 IF BRSE >==4 THEN PSET< £16.. 174. 

530 IF BRSE-4 THEN GOTO 730 

540 IF P=126 THEN 550 ELSE SS& 

550 FOR R=l TO 1+2 

560 CIRCLE CX2.. Y2>..R.. 7 

570 NEXT R 



7" 1 



SO IF PP0INT<X..Y>=7 THEN SOUND 5.. 10= IF PPOINT <X..Y*;'='7 THEN Y=0 



600 

610 
620 
630 
640 
650 



22 .. 1 



•JO 

IF PPOINT<X.. Y>'=7 THEN SC0RE=SC0RE+5 

590 IF PP0INT<F..G>=7 OR PPOINT< T. Q )-7 THEN SCORE =SCORE+10 
IF PPniNKF..G>7 OR PPOINT<: T.Q>==7 THEN SOUND 15.. 1 
IF PPniNT<:T.Q:?=7 THEN T=128=IF T=128 THEN G=0 
IF PPOINT-:: F..G>7 THEN F=33 = IF F=33 THEN G=0 
IF PP0INT(X1..Y1 :5-7 THEN SCORE-SCORE+5 
IF PP0INT<Xl..Yn=7 THEN SOUND 
IF PPOINT <Xl..Yi::'-==7 THEN Yl-0 

eeid FOR Q= 1 TO 1+2 

670 C I RCLEc: X2 .. Y2 > .. Q .. 5 

6S0 NEXT Q 

esf^ IF ppoint<x..y:5=6 or ppoint<xi. 

700 goto 160 

710 FOR D=l TO 5' 

720 CLSC = SOUND D.. 3 = NEXT D 

730 CLS4 = PRINTi512.. "end of game".! 

740 PRINTI244.. "SCORE~" .; SCORE; 

750 PRINT(S£90.. "RNOTHER<Y OR N>".i 

760 IF R!p="Y" THEN RUN = END 



Yl >-S THEN BRSE-BRSE+1 
C=RND< 8 > 

INPUT R* 



Tank killer 

Peter Wales, 
Hereford, 



VJti-'JO 



J 



IJsixo Mi'i;ncoi.orR mode graphics on the 
unexpandcd Vic-20j you can create this 
bombing game. The objective is to blow up a 
tank by dropping a bomb from your super- 
sonic jet while avoiding the tank's return of 
fire. There are 10 skill levels in the game. 
These determine the rate at which the tank's 
missiles home in on you and the speed of the 
tank. 
To obtain multicolour graphics for text. 



Poke 646,12 then use Print. To use this mode 
for graph ics» Poke the colour memory map 
with 12 for the position of your object- To 
achieve horizontal bars in the graphics use 
Poke 36878jl6. To turn them otT use Poke 
36878jO. This is the volume location. This is 
used to flash the plane and create good graphic 
explosions in the game. 

Main program i'mes 

10 80 INITIALISATION 

300 395 MAIN SUBROUTINE 

5000 - 5090 YOUR SHOT ROUTINE 

8000 8135 YOUR W(N ROUTINE 

8140 8440 TITLE INSTRUCTIONS 

90O0 9080 ROUTINE TO ANIMATE TANK 

9910 - 9970 TANK-SHOOTING ROUTINE 



10000 10100 YOU LOSE ROUTINE 

30000 30060 SKILL LEVEL ROUTINE 

Main variables 

P POSITION OF JET 

TB - POSITION OF TANK 

M - POSITION OF BOMB 

TM --- POSITION OF MISSILE 

SN SOUND LOCATION 

VN VOLUME, GRAPHICS LOCATION 

SK SKILL LEVEL 

G$ = TIME 

A$ = KEYBOARD INPUT 

To make the game more difllcuh change line 

5075 to: 

5075 IF PEEK (H + 22 +11 - 30 THEN 8000 
Now you have to hit the tank in the dead 
centre. 



4 PD1 f ft TUO T'*jt£ 4 

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'23/32 (contmued on next page) 



YOUR COMPUTER, MARCH 1983 1 23 



sofrmitSFUi^ 



(continued from previous page! 



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30045 SK»INT<ft>/lO 

30060 00T040 



Psychic asteroids 



J P Riggs, 

Gosporl, 

Hampshire. 



Ji/ii 



WRUINii ti AMI'S on a home compuier can 
pose many problems^ the main one being 
where do I suiri? You can siari designing 
things Uke the layout of the screen, special 
characters and sound elTecis. If the game is of 
the type where you are playing the computer 
the program must contain the logic to handle 
this. Once the program lias been written you 
will want to improve it by speeding it up and 
having better presentation and a more exciting 
game. 

In this program the ship can be rotated and 
The relevant positions must be calculated many 
limes a second to give the etleci of the craft 
spinnings therefore sine and cosine tables are 
set up before the games commences. Other 
ways of speeding up are a program lo remove 
any routines which are wasting time, spaces 
and superfluous text. Simplifying the 
equations before the computer evaluates them 
can save a greai deal of time. 

If you have moving graphics you need ihem 
to move smoothly across the screen without 
disturbing features such as the scores and 
visual information. This can be achieved on 
the BBC by setting up separate graphics and 
text windows, using VDU24 for graphics 
window and VDl'28 for text windows — see 
page J86 of the manuaf 

To make the game more exciting^ better 
graphics and sounds can be developed. The 
graphics are fairly easy to achieve using the 
wide variety of commands such as Move, 
Draw and Plot available on the BBC. The 
sounds arc not so easv to create because the 



Envelope command takes time to master. The 
sounds in this program were created using the 
Knvelope*defming program published in the 
November 1982 issue of Your Compuier. 

The program is a space asteroids game with 
a difTercnce. Where norma! asteroids just 
amble across the screen these contain homing 
devices and high explosives. Just dodging 



them is not enough: you have to blow them 
out of the ether using quick reflexes and your 
laser cannon. Your craft can be moved 
through 360^ and propelled using the 
ihrustcr. 

The control kevs are: FO left turn; Fl right 
turn; F2 a quick 180^ turn; F3, F4, F5 
hypcrspace; F6 thrust; F7 fire. 



>L. 

1 REM BY J.P,R1S6S 1983 

2 REM GOSPORT , HANTS 
10 ONERROR RUN 

20 «0DE7:PRC>Co*f :«FX16,0 

30 DIMS I (V0> ,CO(90> :FORA7,-0TO360STEP4:PRINTTAB(12. 12) S INT( <360-A>l) /36) ; " "; :S 

i < az/4 > "s i nrad i a7- ) : co ( az/4 > =cosrad < av. ) : ne x tax 
40 ♦keyi0"old;mrun;m" 

50 PROCo^f iVDU23,224*24,24,60,60, 126, 126,231,231^23,225,60,69, 153, 165, 165, 153 
,&9,60:NU*^" "+CHR*224;»FX16,0 

60 rRlNTCHR*12;TAB<0.0) iSTRING»<4e,"»">;TABt0, !>"• PSYCHIC ASTE 

R O 1 D 5 »";TABC0, 2>;STRrNG*(40, **♦**) =*FX15,0 

70 PRINT^''*'Do you w*nt background noi««s <Y/NI -:ggg»6ET:*FX9,5 
00 ONERROR GOTO 160 

90 ENVELOPEl, 1,-10, 10, 100,200, 10,200, 120,-100,-4,-1 , 120, 127s»FX10,5 
100 FORX« 1 00TO 128: SOUND 1, 1,X, lsSOUND2, 1, (255-X> , 1 jNEXTi X=INKEY <20) 
110 HIGHSCORE«5!50:HIGHSCORER*»'*a.RIGGS":A*-" ":HS»S50:rtF-l *5 

120 ENVELOPEl,0,^8,-3, 122,227,245, 194, 123,-76,-1,-6,126, 126s ENVELOPE 2, 129,2,4, 
6,28,14, 7,0,0,0, -*80,80, 80 

130 ENVEt-OPE4, 1, 1,2,0,0, 123,1,-110,0,-1,-20, 125, 70s ENVELOPES, 1, 12, 1,3,1,2,12,- 
1,1,-1,-1,126,126 

140 X xy.=RND (901 «4£ ST%=640: RTX«512i A^-^W** : Y07--RTXs X IV-^STX 

150 SCORE-'0iNOLEFT-3s JJ7.«20;PROCaatinit!*TV255,2 

160 MODE4:VIHJ19,0, 1 , 0,0, 0:PROCscoro: PROCcalcs PRCX:«tar ft (400) sPROCdraw 

170 ViXJ24,«<00,^0e,8,00,«t0O,&FF,St04,&BA,«t03 

180 REPEAT PROCcontrol:PROCast«roidiUNTIL MOLEFT<»0iPROC«nd: GOTO 140 

190 I>EFPROCcontrol ;REM Chang© •;>236 TO 7215 AND DELETE 8r.»?237 and 0RB7.« for 0S 

0.1 

200 A%-^236sB7-'»'>237: IFA-/.«160 OR BX=160: XX7.*XX7.'^8#RND(2> sPROCdrawsPROCtes.t <a7.,b 

51,c)!lF RND(3)«1 GOTO200 

210 A7,-?236: IFA%»241 OR B%=*241 1 XXy.-XX%~8»RND<2> sPROCdransPRCXItottt <a7.,b7.,c> : IF 

RND(3)=1 GOTO210 

220 IFA7.*242 ORB%«242 Xxy.«XXy-+lB0:PROCdraw;PRIK;ti?st <a7,,b7.,c) s PROCast^roid 
230 IFAy.»245 ORB%=245:PROCdi stances IF JJ7-><2S*c> PROCthrust <70> sPROCa«t*roid 
240 irAX=148 OR A7.-243 OR A%^244 AS-^'HYPERSPACE" : PROCdraw; PROCteftt (aX, b">C,c > 
250 IFAX=148 OR A7,=243 OR AX-244s IF RND(3)=1 NOLEFT-NOLEFT-1 : VD117: PROCscore 
260 1FA7.^150 ORBX=*1S0 AND RNDCU>0,35 PROCdi^tancir: IF aJX>40PROC'f iresPROCast^r 

Old 

270 ENDPROC 

280 DEFPROCcalc:XXX-(360+<XXX<0>»ABS(XXX)-(XXX>0)»ABS(XXX> ) MOO 360: Xl^- (XXX^IB 

0y MOD 3603X2«(XX7.+215» MOD 360s XS^ (XXX-i-145) MOD 360 

290 IF RTX>945 RTX-5s STX==<1280-STX) ELSE IF RTX<0 RTX=»940sST%»<l280-STX> sS0T03 

10 

300 IF STX>1280 STX*5:RTX-(1024-RTX) ELSE IF ST%<0 ST7.«1275i RTX= ( 1024-RTX> 
310 yX«BI (XXX/4)»3B*RTXsY0X=SI i <X3) /4) «42+RT7.s YT7.-SI C <X2J /4)«42+RTX 
320 X07--C0CXXX/4)*38+STXiXIX*C0<<X3)/4)#42'«-STX:XTX*C0( <X2> /4)*42*STX 

(continued on page 129} 



JUH COMPUTER. MARCH 19B3 





mmi 




1^ 






Bang 1^ 


■ i^^^ mwmssi^m^ 




^^^^^3 H ,^ 


!^^ ■ J^?i^SS$8E9 HI ^^^^^^sx^^m^ 


I'C 








iS:f^ ^JL# 


;::?x->'' 


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ORBITER 



A fast and furious arcade action game for the 
ZX Spectrum. Orbiter is written entirely in m/c 
code with full arcade features including scan- 
ners, reverse, hyper-space, continuous scor 
ing. sound effects and humanoids. 




GROUND ATTACK 



Survival is the name of the game in this exciting 
scramble-type arcade game. Fast machine 
code action with full arcade features. 




MUIMCHER 



Fruiteatingmonsterbeacingmazemunchmg 
creaturecrunchingghostchasingfastamazing 

Muncher! Fast machine code, maze, race 
and chase game. 



' '™ — "^'■"''^sggsiF — """'" "31 


^HT'l^^l 


HBI 


|[^ 


ZX 81 Arcade Action List 






ZX81 Compiler 




i 


£5.95 


Muncher [ZX 81 3 






£4.95 


Asteroids 




J 


£4.95 


Invaders 






£3.95 


Alien-dropout 




n 


£3.95 


Startrek 




1 


£3.95 


Graphic Golf 




n 


£3.95 


Super lAlumpus 




n 


£3.95 


Games Pack 1 




1 


£3.95 


Please send me as 


indicated. 




len 


MAMF 









0", 



;^TARSHIP ENTERPRISE 



Soar through the stars in this exciting new 
space ship simulation. This new, advanced ver- 
sion of Startrek uses the full colour and sound 
facilities of the Spectrum microcomputer. 



D 
D 
D 

n 



ZX — Spectrum Software 

Orbiter 

Ground Attack 
Starship Enterprise 
Muncher 

GENEROUS DEALER 
DISCOUNTS AVAILABLE 

Send to: 

SILVERSOFT 

20 Orange Street, London WC2 

I enclose a cneque/PO for £ 



£5.95 
£5.95 
£5.95 
£5.95 



ADDRESS 



PROGRAMMERS. Tired of working for nothing, send your programs to SILVERSOFT for a speedy reply. 




fe 



I 




^pjp 



yx^ 



BUG«Yn SOFTWARE, MORE THAN A GAMI 



All about me was darkness. Tens of thousands 
of screens stared blankly into space. Minds drifted 
aimlessly, dulled by lack of stimulation. The world 
was grey, drab, lacking . . . 

Then suddenly it happened. First one, then 
another, then tens, hundreds, thousands of tired 
screens felt a surge of power and flickered back 
into life. They were much as I had seen on my 
own planet's microcomputers— the ZX 81, 
ZX Spectrum, Vic 20, BBC Micro and ORIC-1. 



The minds paused to take stock. They clustered 
round the screens, their nimble fingers excitedly 
flicking the controls back and forth. At last they 
had found a challenge . . . action and adventure 
with cunning tests of dexterity and reaction. 
Everywhere, conversation was of Asteroids, 
Mazogs, Panic, Another Vic in the V/all. 

Unable to resist, I too had a closer look. There 
before me was vivid colour, high resolution 
graphics. I could practically feel the spine-tingling 






..irS A DOOR TO ANOTHER DIMENSION ! 



sound effects as whole battle fleets of Cosmiads 
swarmed out of nowhere and attacked. I should 
have known. As my fingers raced over the 
controls, and I prepared to stand and fight with 
only a single laser bolt for protection, I realised 
I was trapped! 

Too late now, I remembered this was no 
ordinary software. I'd been warned, as 1 now 
worn anyone buying from Laskys, W.K Smith, 
Currys Micro C, Spectrum and larger 



branches of Boots, and a nationwide network of 
dealers stocking Bug- Byte. Because Bug- Byte is 
more than a game, it's a door to another 
dimension. One that I had opened. 




100 The Albany, Old Hall Street, Liverpool L3 3AB 




Hoiv Epson beats 
the competition. 

What competition? 




The amazing HX-20. 
The most complete portable computer available today. 



The HX"20 is a portable computer with a full sixe typewriter 
k«Vbo<iKd, ^.^^ Virtual Screen, printer and tnicrocassette focUity 
actually built in. A computer with a rechorgeable power source thaf s 
large enough lor %vriting programs and monipuloting dota virtually 
anywhere^ yet small enough to carry in a briefcase. 

But don'i lot the size fool you. The HX-20 is not a gimmiclcy toy or cm excuse for a 
calculator. It's a precision machine using a full extended version of Microsoft BASIC 
with I6k RAH optionally expandable to 32k and 32k ROM expandable to 64k, 
BS-232C and Serial interfaces. The ASCII typewriter keyboard and five prograrrmiable 
keys brings ten separate program functions to your fingertips. 
Power to your elbow. 

The HX-20 runs on its own power supply for over 50 hours and ccm be easily 
cechoiged overnight, or whilst in use, with the ability to retain its memory in RAM 
&ven when switched off . 
Keeping you in the picture* 

The LCD screen is unique - showing any 20 characters j , 

by 4 lines at n time - enabling you to carry out word ^^ 

processing or data entry as if you are using a large screen. -«« mm 



Print Out. Built Iru 

The 24 column dot matrix impact microprinter otters 42 LPM in a crisp, precise 
5x7 matrix foi perfect hard copies. Every time. And you can choose from a wide 
range of peripheicls from bor code readers to acoustic couplers for total capability. 
Epson. Reliability through Research* 

You'll find our name on a hiylily successful range of computer printers. So you 
can be assured of the same quality and reliability through an extensive research 
progiamme prior to the launch of any Epson product. 

Write or call us for further details and the name of your local stockist (because 
seeing really is believing). 

Just take a glance ct the competition and you'U soon realise that the HX'20 is 
the most portable computer ovailable today. 

Epson (UK) Limited 

Freepost, Wembley, Middlesex HAS 6BR 

Freefone: 2730. Telex: 88141^ 



HX-20 

PORTABLE COMPUTER 




(T at m 



K'j^:'K:}m 



EPSON 



Extraordinary product. 
Exceptional quality. 



soFrnme rnx. 



(continued from page J24) 

330 CXV.mCQ ( ( X 1 > /4 ) ♦! 1+ST7.; CY7.»SI ( < X 1 > /4 ) » 1 i +RTXx ENDPROC 

340 DEFPROCdrawj IF RND(3>-1 AND A*<> *' H YPERSP ACE " PROCaftt^roid 

350 M0V/exOy,,Y'^:PLOT7,XI7.,yO7.: PLOT?, CXZ,Cy%: PLOT?, XTX,Yr/sPLOT7,X0y-,YX 

360 IF A«*"HYPERSPACE" RT7.==RND(950> : STX=RND( 1280) : XXX«RND(360) 

370 A«»"x*' : PROCcalc ; liOVEXOX, Y7-: DRAWXIX, YOZ: DRAWCXX, CYX: DRAWXT7., VT%: DRAWXOX, YXi 

ENDPftOC 

380 DEFPROCthriist <B0%) i SOUND0, -15* I00,8s RTX=RTX+S1 (XX7./4)*BOXsST%=STX+C0CXX%/4 

> ♦BOX: PROCdr aw: ENDPROC 

390 DEFPROC-f i re: SOUND 1 * U 1 , 10: VDU!5 

400 FVX«YX+SI (XXX/4>*JJX;FXX=C0<XXX/4)*JJX^X0X 

410 FORWN-0TO1:GCOL0, 1 : MOVFXOX* YX: DRAWFXX, FYXi PLOT0, 0, 16: PRINTCHR»225 

420 GCOI-0, 0: MOVEXOX, YXr DRAWFXX , FYX: PLDT0, 0, t6= PRINTCHRS223 

430 NEXT:VDU4:PR0Cof #:6CaL0, liIK SQR ( (FXX-aX>^2^{FYX-bX) ^2><25«c PROCdStdest 

440 ENDPROC 

450 DEFPROCasteroid:IF RND<3>=1 PROCdiff 

460 IF 999*89 AND RND<4>al SOUNDRND (3> , 3, RND (255) , 2 

470 PROCt©st2:dZ«aX+KTX:bZ=ibX+JTX:c=c*MF:MF=l/HFsMOVE(dX-10#c> , <bX-10*c) 

480 DRAW(aX+20*c> , (bX-5*c) : DRAW(aX*25#c> , (bX-f25nc) : DRAW<aX+5*c) , <bX+3e»c> 

490 DRAW (ctX- 1 0*€ ) , (bX" 1 0*c ) : PROCtest ( aX, bX, c ) 

500 IFaX>1280 Oft bX>I024 OR aX<0 OR bX<0 PROCtest2:PROCastini t 

510 ENDPROC 

520 DEFPROCstarsCNO) 

530 FORX-^0TO NO:JX=RNDtl280) ! KX=RND( 1024) ; MOVE JX, KX:Pl,0T69, J X,KX: NEXT: ENDPROC 

540 DEFPROC»eor«:PROCof^:IFSCORE>HS HS"SCORE 

550 IF NOLEFT<0 ENDPROC 

560 PR1NTCHR»30;" SCORE^-** ; SCOREl ** HIBH SCORE-**; HS; TAB (25, I ) 5 STRING* (NOt.EFT, 

NU»>;* '■ 

570 ENDPROC 

580 DEFPROCde«troYsVDU19,0,0,0.0,0-NOLEFT=»NOLEFT-|jPROCttCor«!*FXt5,0 

590 SaUND0,-i5,5^S0:FORSX=lT65sFORXPRX=lTO20 STEP2:D^INKEY(2> : VDU23; 13,XPRX,0; 
0; 01 : NEXTs FORXPRX-20 rO0STEP-2; DsINKEY (2> : VDU23; 13, XPRX, 0? 0? 0; s NEXT, : A»« "HYPERSP 
ACE'* iPROCdr.mw!SOOND0. -15,6, 12: A»-"" i VDU19,0, 1 , 0, 0, 0: ENDPROC 

600 DEFPROC©nil:SOtlND2»0,0>0 

610 VDU5=MOVE352,523:PRINT*'G A M E OW E R"; VDU4; ♦FXIS^O 

620 QO*=INkEY(l000) ;*FX15,0 

630 VDU22, 7 SPRINT**^ "••■Your score is "I SCORE;" points**'* 

640 PRINT"High ^core is " ; H I GHSCORE ; •* points, by " ?CHR»129;HIGHSCORER»^ ' 

650 IF SCORE>HIGMSCDRE HI6HSCORE=SCORE: PRINT**Yourii ift tho highast «cor«'":IN 
PUT-*Please enter initials ".HIGHSCORER*' ' 

660 HlGHSCORER*=LEFT*(HI6HSCORER*.4): INPUT^'PRESS RETURN"Ai HS»HIGHSCORE5 ENOPR 
OC 

670 DEFPROCastinit:RANDO«-'RND<-Ti«E> 

680 c-(RND(30)+l0)«(3E-2> 

690 REPEAT: PosX=RND (4 > : aX«RND ( 1 280) • ( - 1 ) * (Po*X*2 OR PosX"4 ) - 1 280 » <PosX^3) 

700 bX=RND<960)»<-l)»(PosX^l OR PosX=3J -950* (Pos'X=2) : UNT ILABS (STX-aX) >40 

7 1 PROCd iff: ENDPROC 

720 DEFPRDCdi f f : DIFFxX» (STX-«X> s DIFFyX- (RTX-bX> t IFDIFFy*/.=0 OR DIFFmX«0 ENDPR 
OC 

730 DX-DIFFxX/A8S<DIFFxX):DY-D!FFyX/ABS (DIFFyX) 

740 IF ABS(DIFFxX> >20 KTX« (RND(5) +8) »DX: JTX=DIFFyX/DIFFxX#KTXs ENDPROC 

750 IF ABS(piFFyX)>20 JTX= (RND( 5) +S>#DY:KTX=D1 FFxX/DlFFyX«JTX: ENDPROC 

760 KTX^10#DX: J TX=10«DY: ENDPROC 

770 DEFPR0Castdest:PR0Ctest2:SC=INT< (SCORE+150-INT(50»C) )/10)»10 

780 PROCex tra: SCORE=SC: PROCscores PROCejcpl osi on ( aX, bX. 65, 2. 2) ; PROCastini t s PRO 
Caster o i d : ENDPROC 

790 DEFPROCtest2:MOVE(a%-10«c) . (bX-10#c) jPL0T7, <aX+20«c> • <bX-5»c) :PL0T7, (aZ+ 
25»c), <bX*25«c) 

800 PL0T7 , ( aX+5»c ) , (bX+30«c ) s PL0T7 , ( aX- 1 0«c > , (bX- 1 0»c ) s ENDPROC 

B10 DEFPROCdi stance: IF RND{3)=1 FF=2 ELSE FF=1 

820 JPX=SQR((a'/.-X0X)^2+(bX-YX)''2):IF JPX<500 THEN JJX=JPX/FF ELSE JJX=JPX/2 

830 ENDPROC 

840 DEFPROCe>:plo«ion(XXX,YYy,ZZZ,WWW)i IF c<0.7 VDUI9, I, 15,0,0,0, 19,0, i 1 ,0,0, 
0sJKK«67 ELSE JKK=69 

850 fORD^-IZl TO 0:IF D>-46 PPX-D/3 ELSE PPX«-I5 

660 SOUND0,PPX*6, 1 ! T= (150+D) *WWW:PLOTJKK,RND(T)-T/2+XXX,RND(T)-T/2+YyY!NEX 
T:VDUI9,0, 1,0,0,0, 19, 1,7, 0,0,0: ENDPROC 

B70 DEFPROCe>itra:QP=(SC DIV 5000) «5000: IF SC0RE>-^3P ENDPROC ELSE NOLEFT*NOtE 
FT+ 1 : VDU7 : ENDPROC 

880 DEFPROCtetit (O, M, E) 

890 PROCdi stance: IF JPX<48 PR0Cdestroy:PR0Ctest2:PR0Castini tsPROCasteroid 

900 ENDPROC 

910 DEFPROCoff SVDU23, l;0;0; 0;0;: ENDPROC: REH Changes to VDU23,8202;0I0;01 for 
0S 0.1 

This program is specif icaify for the BBC mode! B but could be squeezed irno a model A with a few 
changes: in fine 160 cftange f\Aode4 to ModeS; in fine 170 change the VDU24 to accommodate the 
new Mode; in fine 560 the printing will have to be changed to make it neat; as there are four 
colours in ModeS rather than two in Mode4 you can be more adventurous with the colours. 



sse4.d 

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* INTERRUPT INTERCEPT * 
"^ 'i tit on LiSton 3/1/83 

set interrupt liode 2 -and 
initialize inierrupi uector 

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63482 C5 
534S3 DS 




Interrupt-intercept 



Simon Liston, 

Wafthamstow, 
London, 



The ZX SPECTRi'M produces an imcrrupi 
every 0.02 seconds. The Specirum ROM uses 
this interrupt to increment the Frames system 
variable and also to see if any keys are being 
pressed. This short machine-code program 
causes the micro to Call address 63479 on each 
of these interrupts. I have written a real-time 
clock to illustrate one possible use of this 
facility. 

First, reserve some memory; type Clear 
63400. Next, Poke the 23 bytes of the 
interrupt-intercept into locations 65040-65062. 
Nowj Poke the machine code for the real-time 
clock into locations 63479-63665. Check what 
you have Poked with the listing, then Save the 
code you have entered. Next, Enter Rand 
USR 65040. 

You should now have a random time dis- 
played in the top right-hand corner of the 
screen. Hours, minutes and seconds arc stored 
in packed-bed format. Their respective 
addresses arc: 63667, 63668 and 63669. 

Setting the time, for example, 11:44:13 is 
done as follows: 

POKE 63667, ri6-t 
POKE 63668. 4*16 f 4 
POKE 63669, rt6-f3 

Note that you must have a self-contained 
machine-code program at locations 
63479-64760, that is, unless you know exactly 
what you are doing, you should Save all the 
registers and do not alter any system variables. 

It is a good idea lo end your routine not with 
el; ret but wiih JP 56iO) this causes control to 
be passed to the usual interrupt routine. 

The clock program given will keep good 
time so long as Load, Save, Beep, Copy or the 
printer arc not used. Some other ideas: on 
every interrupt. Print the value of the system 
variable PPC to show you the line number 
being interpreted. This provides a simple trace 
mechanism. Or set SCR CT to 255 on every 
interrrupt, this will stop the Scroll? function 
being erased. Why not have a delay loop on 
every interrupt.^ This will slow down program 
execution — if it is not slow enough already. 



push iX 

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(continued on page 137} 



YOUR COMPUTER, MARCH 1 983 1 29 



SPECTRUM 48K : ZX81 16K 
SIX PART ADVENTURE 



■- .. \ '^ '^v' in) ^i 



-, t/m 



5 A^f^i- .:«:... «*;:'«4-..„'; 



'''•■■•■■?^:^>2 





*^ '-3^^ .... ,-;3i^#'" ,<^';: 



^.yc- 



BLACK CRYSTAL 

THE QUEST IS ABOUT TO BEGIN 

The ulitmjit© role playing adventure for the SPECTRUM/ZX81. 
You can become ;i wafnor. o\*. or wtzdrd on a quest to *ind and use 
thcj tin^s of creation: to desirov the Black Crystal and defeat the 
Lords of Cf^aos, Held w»ihjn six pfogfiinis lie$ a land of fabulous 
treasures and mythical monsters. Journey through the (and of 
Bcfoth, explore the castle of shadows, descend into the 
Shagqoths lair, soar cm for diamonds in tho stta of sand but bev/aro 
of sand sftarktfcl Confiont l^'^e fire demon in hi:^ tempfi;, battle 
against \\\e Lo?ds of Chaos arxJ win your way to iha Black Crystal 

By splitting Biack Crystal into six programs we can provide more 
varidty and detail than any other adventure for the Sinclair 
cocnputttfs. 

Real time monster battles. Superb graphtcs. Save game feature. 
All sJx parts are supplied together on cassette, boxed with 
instruction booklet. 

SPECTRUM 48K: 180K OF PROGRAM 

IN SIX PARTS - ONLY £7.50 
ZX81 16K: OVER 100K OF PROGRAM 

IN SEVEN PARTS - ONLY £7.50 

WHY PAY MORE FOR LESS OF AN 

ADVENTURE 



.^^M^.j ^""Tf^^ 




To: CARNELL SOFTWARE. OEPTi 4 STAUNTON RO, SLOUGH. SL2 INT. 
Ptease send me: Black Crystal for my, 

; Spectrum4dK f7.50 

2Xei6K... ,.,...... r7,50 

I enclose a cheque/ postal order (payable to CarneH Software) for E . 

NAME 

ADDRESS , . 



TRADE ENQUIRIES WELCOME 




ZUCKMAN 

ZX81 (16K) 

*ALL MACHINE CODE 

(lOK) 
*FOUR INDEPENDENT 

GHOSTS 
*HIGH-SCORE 'HALL 

OF FAME' 
^AUTHENTIC ARCADE 

ACTION 
♦TITLE/DISPLAY 

MODE 
ONLY £5.95 INC. P&P 



FROGGER 

ZX81 {16K) 

♦MOVING CARS, 

LOGS, TURTLES 
♦ALLIGATORS, 

DIVING TURTLES 
*FOUR 'SCREENS' OF 

ACTION 
*ALL ARCADE 

FEATURES 
♦ENTIRELY MACHINE 

CODE 
ONLY £5.95 INC. P&P 



^t^ ^ 



DRAGON 32 SOFTWARE 



i<. %n, 



MISSILE COMMAND ONLY £5.95 

FULL HIGH-RESOLUTION COLOUR GRAPHICS + SOUND 

GRAPHICS DEMONSTRATOR 0NLY£5.95 

LEARN THE SECRETS OF HI-RES GRAPHICS PROGRAMMING 



DJL SOFTWARE 

DEPTYC. 9 TWEED CLOSE. SWINDON, 
WILTS SN2 3PU 

TRADE £NQUmieS WELCOMe 






SOUND With SINCLAIR 



MAKE AMAZING SOUND EFFECTS 
WITH YOUR ZX 81. 
TIMEX Sinclair 1000 
or SPECTRUM 

THE ZON X 
£25.95 

inclp&p&vAT 

"k The ZON X SOUND UNIT is c nptetety seff-coniained and especially 
designed for use wiih the ZX 61, TIMEX Sinclair TOOO and Spectrum 
CofYiputers. It jMSt pk>^ in — no dismatliivg Qt soldering. 

if No power iMCks, batteries, leads or other extras.* 




ampte voturtw from built*m ^ud- 



^ ManydJ Volume Control on p«nel 
speaker. 

^ Starvdard Sinciair — 16K Rampack or primer can be plugged into ZON 
X Sound Unft without affecting notntal computer opera lien. 

'A' Hus« rarvgo of possible sounds for Gam«s. Music^ Ke&coptert, Sct-Fi, 
Space Invaders, Explosions, Gun-shots, Orums. Pi»ne«, Lesers, 
Organs, 8eifs> Tunes, Chords, etc.. Of whatever you devise! 

lAr 8 full octaves. Uses 3'Channel sound chip giving programme control 
of pitch, volume of tones and ru>ises, all with envelope control, 

^ Eaciy ^66t6 to existir>g gan>e3 or programmes us»r>g a few simple 
"BASIC" lines or machine code. 

iK No memory addresses used • 1.0. mapped. 

FULL instructions with rrvany examples of how (O obtain effects and the 
programmes, supplied, fully guaranteed, British Made. 

*£xccpt wfth $p€C(ntm, you fjced the Spectrum ixtensfon Soefd Order 
No. S£f - Pnce £€,$0 ina V.A.T. 



Payment may be n^de by Cheque. P.O. 
QiTo No 3® 7006. Postal Order or Credit 
Card. 



Export orders :- Bank Cheque, 
tnternational Morvcy Order. U.S. % or £ 
Sterling, 




YOUR COMPUTeR. MARCH 1 983 



soFnums nu. 



(continued from 


page 


;25; 


^^ec 










5364S 


11 


00 01 


Id de.2S& 










5 2609 


FS 






push &f 


6364S 


06 


08 


I d b , » 


S3SS8 


DD 


21 


18 


4C t.<i i^X|164.06 


53610 


C6 


3F 




sr I a 


Uc 








63S62 


3R 


63 


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Id a f (Hour*) 


63612 


C6 


3F 




sr t. a 










S3S65 


CD 


79 


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call Pd&c 


6361* 


ce 


3F 




* ri a 










S3S68 


3E 


OP 




L d a . 10 


53616 


CB 


3F 




sr I « 










O3S70 


CD 


SC 


F8 


call Pch 


3361S 


CD 


SC 


F6 


cai I PCh 








Id a,thl» 

xor ass 

Id ClX+01 ,% 


©3573 
63ST6 
53ST9 


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CD 
3E 


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Fe 


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Fl 






pop a r 


63650 
63661 
S36S3 


7E 
DD 


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S35S1 


CD 


SC 


F8 


call Pch 


53622 


£6 


0F 




and IS 


53656 


23 




inc hi 


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3R 


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F-5 




53624 


CD 


SC 


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call Pch 


53657 


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19 


Add i X , d€ 


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79 


F3 


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53627 


C9 






re I 


536S9 
63661 

63663 


10 

DD 

DD 


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El 

23 


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pop ix 
inc i X 


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21 


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53665 


C9 




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635^3 


06 


03 




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63626 


DD 


es 




puih ix 










Ql 










63630 


2R 


36 


5C 


Id hi , f 23606) 










53595 


36 


C7 




Id (h li . 199 


53633 


11 


30 


01 


Id de^304 










o3Sg7 


33 






i n C hA 


63636 


19 






add hi,d« 


^«a I 








53S93 


10 


^^, 




djnz At 


53637 


Be 






ex de.hi 


defb 50 






63&0O 


£1 


\ 




pop K*. 


63633 


6F 






Id I ^a 


Hours 








63601 


Dl 






pop de 


63639 


26 


00 




Id h >0 


63667 


00 




nop 


e360S 


CI 






pop bC 


6364.1 


29 






add h I . h I 


^1D5* 








53603 


ri 






pop «f 


63642 


29 






add hi ^Hl 


53666 


0O 




nop 


63604. 


DD 


ei 




POP ix 


63643 


29 






add hl.hJL 


Sec 4 








63606 


C3 


36 


©0 


^P SB 


53644 


19 






^dd Kl^de 


53669 


O0 




nop 




























% 



Chords 

Bernard Dembowski, 

Feltham, 

Middlesex. 



J}^J 



Three TYVES of chord are described by this 
program: major, minor and seventh, Each 
chord consists of eight notes played in rapid 
succession, similar to the banjo cross-picking 
style. A bar — four beats — requires 16 notes. 
Within the confines of this Forth program, if 



one chord lasts the length of the bar, you enter 
it twice. In other words, one chord entry 
equals two beats. 

Now for the program. First enter a variable, 
T; this is the length of each note in 
milliseconds. This governs the tempo of your 
tune. Next, define the word Chord, then 
define the chords you need for your tune. The 
Jupiter Ace*s memory is not sufficient to store 
all the chords shown, so just define the chords 
you need. Unfortunately, this method is not 
suitable for waltzes, that is, anything in three- 



four lime. In the example the chords are 
written out exactly as you would enter them 
into the Ace. 

Michael, row the boat ashore 

150 Tl 

DDDDGGDDF#mF#mEmEmDA7DD 

House of the Rising Sun 
200T ! 

Dm F G Bb Dm F A7 A7 Dm F 
G Bb Dm A7 Dm F Dm F G 
Bb Dm F A7 A7 Dm F G Bb 
Dm A7 Dm Dm 



lOO yflRIRBLE T 


: n 426 358 284 426 353 284 426 358 CHORB ; 


: CjlORB 8 JO T ? BEEP LOOP j 


: U 379 284 239 379 284 239 379 284 CHORB 3 


( mm ) 


: EH 379 319 253 379 319 253 379 319 CHORB 3 


: C 3i9 379 239 319 379 239 319 379 CHQRB ; 


: IbH 358 451 268 358 451 268 358 451 CHORB 1 


; F 179 353 284 179 358 284 179 358 CHORB J 


: EtH 338 268 402 338 268 402 338 268 CHORB ] 


: 6 319 426 253 319 426 253 319 426 CHORB J 


: «tH 402 301 253 402 301 253 402 301 CHORB 3 


: 1 338 426 284 338 426 284 338 426 CHORB j 


: BbH 379 301 451 379 301 451 379 301 CHORB j 


: ft 284 379 451 284 379 451 284 379 CHORB j 


: 6«>HCF«H) 338 284 451 338 284 451 338 284 CHORB ! 


: E 361 379 253 301 379 253 301 379 CHORB j 


: Hi 426 338 253 426 338 253 426 338 CHORD ; 


: lb 353 426 268 358 426 268 358 426 CHORB 3 




: £(,319 402 268 319 402 268 319 402 CHORB ) \ 


[ SEVENTH ) 




: C? 379 319 268 379 319 268 379 319 CHORB 3 


: fit 301 402 473 301 402 478 301 402 CHORB I \ 


: F? 402 358 239 402 358 239 402 358 CHORB 3 


: Bk 301 358 451 301 358 451 301 358 CHORB j < 


: 6? 426 358 253 426 358 253 426 358 CHORB j 




; 17 426 338 239 426 338 239 426 338 CHORB J 


: QtCF*) 268 338 451 268 338 451 268 338 CHORB j 1 


: R7 379 319 451 379 319 451 379 319 CHORB 3 


: 1 253 338 402 253 338 402 253 338 CHORD 3 i 


; E7 426 379 253 426 379 253 426 379 CHORB 3 


( HIHOR ) ; 


; lb? 358 301 426 353 301 426 358 301 CHORB 3 


: Ul 402 319 451 402 319 451 402 319 CHORB 3 


; CH 402 319 239 402 319 239 402 319 CHORB 3 ; 


t Rfc? 402 338 239 402 338 239 402 338 CHORB 3 


: f« 358 301 239 358 301 239 358 301 CHORB 3 \ 


; Ib7 358 301 253 358 301 253 358 301 CHORB 3 

; 6t>7(F*7) 338 379 451 338 379 451 338 379 CHORB } 


: GK 426 319 268 426 319 268 426 319 CHORB } 


\ 1? 338 284 402 338 284 402 338 284 CHORD J 



Stuntman 

C Szponjnarowicz, 

Hounslow^ 

Middlesex, 



mi)iZ\ 



Stuntman uses high-resolution graphics, and 
creates realistic motor bike sound effects. The 
program fits into 2.5K but high-resolution is 
also needed. 



The basic idea is that the motorcyclist has to 
jump as many buses possible. To acquire the 
correct speed, press Control to accelerate, 
Shift to decelerate, and Repeat to jump. The 
correct speed is equal to the number of buses 
multiplied by 10. 

The exact speed would be too difficult lo 
gel, so at the start of the progam the skill level 
is asked for. Now the speed to successfully 
jump all the buses is greater than the number 
of buses, but less than the number of buses 



combined with the current skill level. 

There arc two starting roads before the final 
road, where the correct speed has to be 
attained. If you travel too fast, the bike crashes 
into the ramps. If you travel too slowly, the 
bike will not generate enough speed and will 
fall killing your man. If you attempt to jump 
before the third road, the bike crashes, losing 
one of your three lives. 

When the roads have been drawn, and the 
(continued on page f33) 



YOUR COMPUTER, MARCH 1 983 1 31 





From Scotland's Capital comes qualify software for ttie 



ZX Spectrum, VIC 20 & now also Dragon 32 



The Quest 

(48 K - Spectrum; Dragon 32 > 
(Omi' of the most exciting adventure 
games currently available), Fight your 
way in(o the depths of the complex in 
your Guest for the Holy Graii. Discover 
Gold and Precious stones, buy weapons 
irid Magic wares from a trader Battle 
with one of the many^v Monsters. Up to 
1500 locations may be searched in the 
course of a game. Full sound effects and 
save game facihty. Only E5.00 

Star Trek 



'^•'^ Star fighter 

M8K - Spectrum; 16K - VIC 20; Dragon 32) i->.^ Crt-i^fr..r«l 
lyiake your way through the under ^^^^ bpecirumf 



gioufid labarynth tn your search for the 
dreaded Orb, which you must desuoy. 
Encounter many Monsters, discover 
Treasure and try to remember your 
route so that you can get out again. Full 
sound effects and save game facility. 

Onfy £5,00 f 

NEW! 3-D Maze 



, -,., ^, „^ rtrt (48K - Spectrum; Dragon 32) 

save game facihty. Only E5.00 . ^ 

Exciting 3 Dim*MiM<>n*il Ma/f* Garne» 

Star Trek Secuch (or thi* 3 lahutous tr*M<;ures. Ihon 

(16K Spectrum; 8K - VIC 20; Dragon 32) .^lak** youi way iMtk to thr vxiu Tim** 

r»**v<! the G.ilaxy from rhe Khngons usniti yours<*1l with ilie On ScM'i»n Clock 



your i4ipid lire phasers dnd photon 
t'lrfwdos. Automat ic short range scan. 
Galaxy map and Star bases. 
Full sound effects and 10 levels of 
difficulty* Only fb.OO 



yoursi'll with ilu! On ScM'i'n Cloc 
But Bew.ire the treasur**'^ nfo 

always in llie s*imi' liKriitonv 
Only C5.00 

Oeali.'rs Alli.u tivr Dim ohms 
Sperlium fir VIC ?() pMH|i.iinrti( 



ALL ORDERS DESPATCHED BY RETURN 



?b% Royal lie 



1 enclose a Cheoue/PO. foe C 



Name 

Address _. 



Please Supply 

The Quest (C5 00) D 



Post Code. 

All prices includa P&P and VAT 

IMPACT SOFTWAFie 
70, Redf Of d Avenue 
EDINBURGH EHT3 0eW 
TEL 031-441-4257 



3D Maze (es OOJ D 

— Ofb(C500) a Starfi9hte<<CS<X)> D 

Siaf Trek (£5 00) D Games PackfCSOO) D | 

Please state machine type — , 



All action, fuHcolour, graphic machme- 
code. Space-battle with devastating 
explosions. On screen scoring and high 
score kept. The longer you survive the 
more difficult it becomes. - Only £5 00 
Games Pack (Unexpanded VIC 20) 
Ahen • Hoati Race ' 
The Island • Pontoon ' 
Only C5 00 






I 



I'M 









Uictagraph 



plot uiindoui 






An essential aid to all computer owners with Plot, Draw 
or similar, to an absolute and /or offset co-ordinate. 

Now Compatable with 
ZX Spectrum 

Are you finding ZX Spectrunns Plot, Draw difficult and 
stow to work out? . , . Yes , . . 

Then you need Victagraph Plot Window. 

Place your drawing etc. in the Victagraph and you are 
ready to plot all the points, using the movable window 
mask, offset screen and easy to read scale. Victagraph will 
also help with circle, and parts of circle with the ZX 
Spectrum, All this without graphpaper. 

Total price £7.50 - Cheques/P.O. — payable to Victa 
Ceramics. UK only. 

VICTA CERAMICS 

6A BOW STREET, RUGELEY 

STAFFS. WS15 2BT. 



STAH 
SOCCEI) 







AN EXCITING NEW GAME 
F0RTHEZX81 {16K) 

ALL THE ACTION OF REAL FOOTBALL 
PASS - SHOOT - DRIBBLE - TACKLE 
CORNERS - FREE KICKS - THROW-INS 

YOU PLAN THE MOVES - SEE THE PLAY 
IN HIGH SPEED GRAPHICS 

MATCHES BETWEEN 12 TOP CLUB SIDES 
AND 12 'STAR* WORLD CUP SQUADS 

MORE THAN AN ARCADE GAME 
MORE THAN A SIMULATION 

'A truly original and absorbing game' 

ONLY £5.95 

Please make cheques and postal orders payable to: 

Watson 6oriware 6er vices Ltd. 

1, Ivy Cottages, Long Road West, Dedham. Essex C07 6EL 
Allow 14 days for delivery 



132 YOUR COMPUTER. MARCH 1983 



(continued from page 13 ft 

bike appears at the top of the screen^ press any 

key to start. This happens each time the bike is 

positioned at the top left-hand corner of the 

screen. 

The first Hne, retains the high score — value 
of H — even if Break has been hit, but set the 



soFTvmsme. 



value to when the program is first loaded. 

In some places — for example^ 8000-8300 
and 9000-9300 the Plot statement has been 
used instead of Move and Draw. This is for 
ease in typing. For example once lines 
8000-8300 have been typed, it is a simple 
matter of editing these hnes, changing the line 



number to 9000, 9200 and 9300 and changing 
the Plot 13 to Plot 15. 

Line 8100 does not have lo be edited 
because it is used to delete remnants of the 
bike before the ramp. This editing can a!so be 
used for lines 270 convened to 307 — 
remembering to delete the Goto variable i. 



1IFH<0 H=0;REM stunt HAN 

5P,*12" STUNT hAN'"" BY C ♦SZfOJNAROHICZ 1/1/83"' 

6P."THE OBJECT OF THE CAME IS TO JUHf> ftS hANY eUStS AS" 

7P»" POSSIBLE.**" "THE CONTROLS ARE CTRL-ACCELERATE"' 

8P . " SHIFT-DECELERATE " ' " KEPT-* JUMP" ' 
lOP. ""SKILL LEVEL"' 

11in."1 impossible to 100 easy" 'j 
i3L'=ojs=io;a^i5o;x^5o;y^30;u=-2;i==15i;z»ijv«'1.io;w«3(» 

l4G«-lJK=V-X-40;T = 5a?N»50JH*30;F=^J 

JSOCLEAR^ 

200dF*«^0TOirS6 S*2;PL0T13,Qr (A-DfM.Q 

210F,Q»lTO257 S.2; PLtlT 13,Q , ( A-2) JN.Q 

220F,OeOT02£.& S. 2 J PLDT13,a, ( A-3) ;N.Q 

230A-A-60SIF A>1U G.d^A^^SO 

250REH ORAM RAUP 

2701 PLOT IS, VfWjF-LOT/ttV-l^) , < W+ 10 ) JPLOTZ, ( V-19 > i M;PL0T7 t V,H 

275V-V+10 

300REM BIKE 

301sPLOT13rX,Y|PLOT5»lX+i9>,tY*10) JPLOTti, (X* 19 > , Y;PL0T5,X, Y 

302IF TOlOO G,2 

303pS=10K2JU=2;i«15i;Z*l#X»St>;Y»30 

306PLOT13,X,y;PLOTO»(X+19>,(Y^^10>;PLOT5,(X+19),Y;PLDT5,X,Y 

307PLOT13,y,HJPLQT5,(V-l9), CW+10);FLOT5^(y-19>,H;PLOT 5,U,W 

30aPLOT13,U,I 

309LI*£FFE3 

310t*PlOT15*i.M ;n:=iKZ;PLnT13,U,I 

312IFI«31 AND U>(X*20> G,d 

313IFI«31 PL0T15r (X-3) , <Y+1 > JPL0T7^ (X-1 > , < Y+1 ) 

315'>£BO02=5J?£6OO3 = ^ 

330IFU>=25A 1=1-60 

33SIFU>=-2S6 U==0 

3^0IFZ<1 Z=l 

3SOIF'>£B00i&£'»0«0 2<^Z+l 

360IF?£B002<128 Z»Z"1 

370IF?£B002«£^0»0 C.c 

400 G*b 
2000CIF I031 Q*t$ 
2010S«-10wZ;K"M-X~40 
2030IFU<(X-1) C*b 

2040IF?£B002lt£10»0 AND U>CX-10> U«X 
20S0IFU><X+1> G»d 
9OOQREM JUMP 
3020IFS<K G*t 
3025IFSXK + J) G*d 
3027G«e 
3030IFS<K C.t 
3031IFS>(K+J> G^d 

3032tPLOT15|U,i;U=U+2;i«I+UPLOT13,UrI 
3O33'>£B0 02=5;?£bOO3=4 

303iHAIT;MAIT;HAIT;HAIT;iFU<64+(K/2) G.t 
3035rPLOT15,U,IJI»I-i;u=U4'2;>£B002«5;?£B003«-IJPLOTi3#U,I 

3036hait;hait;mait;mait;ifi>4i c*r 

3037G.d 

3040IF S>(K+J> G*d 



3045G*« 

3090G.300 

50 OePLOT 1 S , U * 1 ; U-U+2 ; I»l* t 

5005PLOT13*U,I 

5006WA1T;HAIT 

50O^7?£&OO2'5;?£DCO3«4 

5008IFU><X+19>+<K/2) G.f 

5010G.O 

600 0fPLOT15rU,IJU=sU^2;i'I-i;PLOT13*U,I 

6002?£800 2='5;?£B003«4 

6oo3wait;hait;hait 

6004IFI>31 G*f 

6100I«31 

6105PLOT15rU,i;u-U*l!PLOT13»U>I 

6110?£B002»=5;?£6O03=4;WAIT fWAIT 

&120IFU<U+20G,6100 

6l22F*F-(F/3) 

6123T-50;2-l 

6127PL0TlSrU,i;G,i 

6130iG.270 

7000uirK-20 K^O 

7005D«<K/10) 

7010 P.$i2"YaU HAVE KILLED 3 MEN YOU JUMPED" 

7050P.D" BUSES"' 

71 OOP, "YOUR SCORE HA8"K 

7130IFK>H H-K 

7140P* '"AT SKILL LEVEL" J 

7150P*'**THE HIC;H SCORE IS"H 

7250IN. '"WOULD YOU LIKE ANOTHER CO "♦T, 

7300 IF?T*^CH"N" £, 

7350IN**'MOULO YOU LIKE INSTRUCTIONS "*T. 

73&OIF'>T,=CH"N"G.10 

7370G.5 

7400E. 

8000dPLOT13t <U+2> , tI+2> {PLOTS, (U-2> , <I-2> 

8 1 OPLOT 1 5 p < U~2 ) , 1 J RLOT 7 , ( U + 2 > » I 

820DPLOT13, (U-2 > , <l-fr2> JPL0T5, <U^2> ,(I-2> 

0300PLOT13,U,<I+2) ;PL0T5,U, (l-?> 

83tSOF*Q^01U4i»o;?£fc?002^u;N*C4;Z=i;PLUTl^,U,i;L^Li^l 

B56flIF L«3 G.v 

9000yPl DTl5,(U+2) * (1 + 2) JPL0T7,(U-2>, <I-2) 

9/00(^1 OTIS, tU~Z> » (1 + 2) ;PL0T7 . tU+^2> , (1-2) 

9300PlCiTlS,U,<l + 2);PL0T7rUt<I'-2) 

9350T^IOO 

9400C*S 

9r.002F'LOT13, <N+2l> ,MJPLOTti, <N4^22) ,M 

9510FLOT13*(N+27),M ; PLOTtJ, CN+2B> ,M;M»^M4 1 ; IF fl<32 G.z 

9520wPLOT13r (Nf2l)rM;PL0T5r<N^^28;,M;M«^M+i;iF M<40 G.w 

95*^51^ '30 

9U27M0VE<N*22) , (M* 10 > JDRAH(N + 27> , (M*^10> 

9530PLOT15, (N*23> , (M*^0 > ;Pl 0T7 , (N*26> , (M + B) 

9532PL0T15, <N+23) , (M+7 > JPLOT? , <N*^26> , (M^7> 

9S33N=N+10 

9535G=C+i;if G<(K/10> G,2 

95^0G,p 



Hi-res mover 



Jan Erik Lundberg, 

Sofna, 

Sweden, 



'^ 



mjstjrjiDzi 



Impressed by the smooth action of the hi- 
res graphics in Psion*s Planetoids for ihc 
Spectrum I just had to have a go at writing a 



machine-code subroutine that could do a 
siniilar job. I hope that it will be useful for the 
readers who want to write their own programs 
using moving graphics. 

Overcomplicated Basic programs would be 
too slow but perhaps a compiled version 
would be better. 

The demonstration driver program is only 
intended to show how to use the routine and 



demonstrate its good and bad features. 
See what happens when you change t|ie 
mode — to 3. The subroutine writes or 
erases the user-defined graphic in high-res — 
172x256. You can expand them from 21 to 
32. It is position-independent coded> PIC> and 
you should start to load it 600 bytes lower than 
the UDG pointer. Perhaps it is easier to load it 
directly from the memory dump. 



1 
& 

3 
X& 
IS 
3t& 
3fi» 
4.0 
*S 
SO 

ss 

56 
60 
51 
&2 
63 
70 
71 



^X/t \ 



n^n His- I ..^ MCvt r 

POKE a3ee3,3i& 

►;:£STORE 300O 

r* iR d.rC*5fteO TO 3^33B 

P;^R-'' n: POKE S^n 

N£XT a 

RESTORE S» 

FOR ':i=:s2^EK'i TD ^^a6«e 

R^mo n. POKE d^rj 

NEXT d 

LET xa=2372» 

yet bX« -fl 

Cha=23e77 

haoo schawl 

14.4.^ =c ode <« 1^4. troytrf be 
expanded ic «ax 3i b^i 

7a REM lio^l colour chflpnofr di*-- 
sabie* bqbb FiO rmsxorin^ 

Se LET XmXe^ 

85 LET y«3fi 

as BORDER B: INK 1: Pfif>ER 6^ 

ii>3 LET Xf«l: LET y r «a 

©0 PRINT nr 0,0; Ink i;'> 



L*T 
LET 
LET 
REM 
REM 



9S roR 



PRJInJT ^T i ,e 



INK 2; " 1 

I •' f NEXT i 
93 FOR i fcl TO S3: PRINT i=>T RWD 
*30*-*S^RND*3©+.5; **V ^" : NEXT i 
95 POKE ttOd,£: REH "ftdt" mOdC: 
98 POKE ChM^S: REM writr r^d * 
X00 POKE V&^V 
A0a POKE X3,x 

105 LET t =U6R 3^tfi0i^. PtEti »ritB 
10© ir \-=l THEN PRINT RT ;£,50,* 
MIT'*; BEEP .a,S0 
109 IF 1=0 TMEN PRINT RT £<-^0;*" 

111 IF JNKEY»*="S" THEN LET Xf^- 

lis IF lNKEY*a'*&" TMEN LET Xf»5 

113 IF INKEY»=*7" THEN LET yj" -1 

lid IF INKEY* = "6" TMEN LET vrs*- 
1 

115 LET x-x+xr 

117 LET y»y+yr 

119 LET I=U^R 3S004.; REM l?rd5-t 

120 GO TO 100 
1099 STOP 

3000 REM finds ttover pom t er IX 
write cr*se flag (in * i* " > cii'^rs^ 
a3©7e for later ur-* ** hit »nd 
colour change ridgs 

3010 DRTR 175,S5,24., 1 ,17S:, 71,^.3 
3 , 1S& , 9^ , 1 P& , 230 , 7 , 1 1© , *? , l^G , fl^3 
, 248 , 79 , 126 , 230 . 7 , Al? . 1*3 , & 7 , li2& 
, 230 , 24a , 176 , 1 19 / 221 , 42 , 123 , 92 , 2 



21 ,9, 17, 139.255^221 ,2S 

3050 REM 5ets attrpointrr ftfcc^rd 

ing to Y. pusbs it on s^thCt AND 

leaver witK a ay mod 192 

3060 DRTR 33.2^4.^90,14.32,39,177 

*9»^214,19S.4.B,2,19ei.l92>95.22,© 

, 1©7 , 237 , 66 , 14.5 , AS . ;S'S;i , l6ci , 9 . 229 

3100 REM sets picpointer ml »ccc< 
rding to y »nd lenvcs D loitb i i r. 
es left in roi*, Etfith 1 if ro4*rv 
rewarnias for banxsbi/t> 

3110 DfiTR 33,224.87,3^,14.^4.237 

.©2. 145. 4©, 251 ,129.25,14,32,30.9 

. 29 . 237 , ee . 1 45 , 41? ,250 , 1 30 . 9 . 134 . 

40 .5 . 21 , 37 , 6 1 , 3:^ , 251 

3150 REM adjust poirittrs for x 

And pK.xs>h aitrpoJntirr on b-xack 

c=rest in x* b«& tines to scsrn 

3150 DRTR SB, 176,92.1ff4,4i?, 12.19 

3 , 35 , 3 . 214 , S , 4a , 250 , 19a , a . 4:^ , 1 1 . 

197.79.6.6 

3300 REM »ain line scan loop 

writes or er»s6S^ thir dotjf. ,5^ets 

UP the flag re9is.ier for i*tcr 

\js^ in colour part 

3305 REM Adjusts dtl data for re 

3310 DRTR 197.213.229.121.221 .7© 
, 124 . 14 . . ee . 35 . 94 , 221 . 102 , 132 . 1 

(continued on page 735} 



YOUR COMPUTER, MARCH 1 983 1 33 



lntroducin< 



gsof 



^ABt 



,UPB» 



CttESS 



For S\nc\au 



THE BEST at £7- 95 

Guaranteed able to beat Sargon II 




and all other Spectrum chess programs ! ! ! 

JSix levels of play 
Plays a variety of openings e.g. French Defense, Sicilian Defense, 
Ruy Lopez, Queen's Gambit etc. i^ Self play mode 4^ Analyse mode 
1^ Enhanced end-game play i^ Recommended move option 

Available only from the address below - dealer enquiries welcome 

••ORIGINAL SUPERCHESS^^The Cheapest 

10 levels of play : recommended move option : substantial 'opening book' e.g. French 
Defense, Queen's Gambit, Ruy Lopez etc : self play feature 48k Spectrum - £4.95 

: analyse mode. 16k ZX81 - £4.95 

••ZX DRAUGHTS •• 

Did you know that a computer draughts program has beaten the world draughts 

champion? 

Draughts is an ideal game to apply tree searching techniques to. Our program analyses 

each position in depth making it a formidable opponent. Choice of colour. 10 levels of 

play, at level 6 (response time - 20 seconds) it beats 



Its own programmer! 






48k Spectrum - £6.95 



BACKGAMMON 



Play this fascinating game of skill and chance. 
High resolution colour display with dice roll. Can be used 
by expert players and also has documentation to enable 
beginners to learn the game. 48k Spectrum - £5.95 



••SPECTRUM SPEECH •• 

Yes it's possible! Software driven speech from the Spectrum. Simple to use in your own 
programs. Each cassette comes with user documentation and demonstration program. No 
extra hardware is required. Uses Spectrum speaker and top 32k Ram. 

SOFTALK I: 'Multiwords' 7Qf words, numbers zero to million, plus, go, limit, right, 

great etc . . . 48k Spectrum - £6.95 

SOFTALK II: 'Spacegames' 80f words, numbers, red alert, torpedoes, phasors, 

bearing south etc. . . 48k Spectrum - £6.95 

••SPECTRUM ASSEMBLER •• 

An essential aid for m/c programmers. User documentation supplied with 

each cassette. 1 6k and 48k Spectrum - £4.95 



UK Prices include post & packing. Despatch within 48 hours of receipt of order. 
(For orders outside UK add 80p for postage) 

Send cheque or postal order to: 

CP SOFTWARE, Dept.YC, 17 Orchard Lane, Prestwood, Bucks. HP16 ONN 



PROGRAMMERS - TOP RATES PAID FOR HIGH QUALITY SPECTRUM 

STRATEGY GAMES AND SPECTRUM FORTH. 

SEND YOUR MATERIAL FOR EVALUATION AND PROMPT REPLY. 



1 34 YOUR COMPUTER. MARCH 1 983 



SOnWAKEflU 





33168 


230 


185 


40 


14 


32172 


203 


230 


24 


lO 


32176 


184 


40 


2 


203 


32180 


246 


185 


40 


2 


32104^ 


203 


284 


8 


48 


32iae 


2© 


8 


22 X 


126 


3S19S 


124 


182 


40 


8 


32196 


203 


214 


203 


7© 


322O0 


40 


2 


22 


e 


32204 


221 


114 


132 


335 


32208 


225 


126 


176 


119 


32212 


35 


126 


177 


24 


3S216 


15 


8 


209 


225 


32220 


120 


47 


70 


160 


32224 


178 


119 


35 


121 


32228 


47 


78 


161 


179 


32232 


119 


43 


209 


193 


32236 


221 


43 


21 


40 


32240 


5 


37 


16 


134 


32244 


24 


28 


5 


40 


32248 


25 


4 


229 


33 


32252 


126 


92 


203 


222 


32256 


225 


197 


1 


224 


32260 


6 


29 


40 


4 


32264 


9 


193 


24 


230 


32268 


6 


255 


9 


193 


32272 


24 


224 


33 


14 1 


32276 


92 


6 


46 


2 


32280 


48 


143 


8 


126 


32284 


46 


126 


209 


203 


32268 


88 


40 


4 


203 


32292 


70 


32 


2© 


1 


32298 


223 


255 


203 


102 


32300 


40 


1 


18 


19 


32304 


203 


110 


40 


1 


32306 


18 


235 


9 


235 


32312 


203 


118 


40 


1 


32318 


18 


19 


203 


126 


32320 


40 


1 


16 


1 


32324 








8 


5© 


3232© 


2 


203 


150 


203 


32332 


86 


200 


12 


201 


Chechsun > 


.347S3 







(continued from page 133) 

05 , 185 . 40 ^ 15 , 203 , S6 , 203 , PS .203 , 6 
, ^03 . 29 , 203 . 35 , 203 , 1© , 61 , 32 , 241 
3320 REH mriXB Of eras-e- and j-«t 

up f i ags 
3330 DATA 229,33,126,92,203*94,3 
2 , 12 , 184 , 40 , 2 , 203 , 23i? . 1 ©5 , 40 , 1 4^ 
203 , 233 , 24 , 1 , 134 , 40 , ^ . -?03 , 246 , 1 
85,40,2, 203 , 254 , 8 , 48 , 28 . i5 , 221 , 12 
6, 124, 162, 40, ©,203, 21 4, 203, 78,40 
, 2 , 22 , , 22 a , 1 14 , 132 , 225 , 22S , 126 , 
1 76, 119, 35, 126, 177, 24,1 5, i*, 209, i? 
25, 120,47, 70. 160,178,119,35,121 , 
47,78,161,179,119,43, 209 , 1 93 

3400 F^CM ^n^ Of Btain scanBing lo 

OP ^ Pdjusis point* ri- for nt-xt 

byte to be wf i t ttn 

3410 DATA 221,43,21,40,5,37,16,1 

34,24,28,5,40,25,4, 229 ,33,126, 92 

,203^222,225, 197,1 , 224 , 6 , 2© , 40 ,4. 

, 9 , 193 ,24 , P30 , 6 , 255 , 9 , 193 , 24 ,224. 

3500 ntH writes th* appropriate 

attributer* and return* with bc«ia 

i ( &n^ hit 

3S10 DATA 33,141,92,8,48,2,46,14 

©4 , 70 , 32 , 2S , 1 , 223 , 255 , 203 , 102 , 40 
,1, 18, 19,203,110,40,1 ,18,235,9,2 
is, 203, 116,40. 1 ,18,19, 203,126 ^40 
,1,1©,1,0,0.S,»6,2,203,I5O,*;03,8 
b>200.l2,201 

8000 FOR 3 =32000 TO 32335 5TEP 4 
8010 LPRINT a;" ";PeeK a ; TAB IS ^ 
PCCK f^*l);TA8 18;P£^K ia+2J,TAf? 

S4;PEEK fa+3> 
e©20 NEXT a 
6330 STOP 
^000 LET 5UJl*0 
Sei0 FDR ^1132000 TO 32335 
9O20 LET au»i»SUIA4-PEC:k a 
9e30 NgXT a 
9040 LPRINT "Chechs-uw »";»li» 



32000 


175 


55 


24 


1 


32004 


175 


71 


8 


33 


32008 


126 


92 


126 


230 


32012 


7 


119 


45 


126 


32016 


230 


246 


79 


136 


32020 


230 


7 


46 


143 


32024 


©7 


126 


23© 


248 


32028 


17© 


119 


221 


42 


32032 


123 


92 


221 


9 


3203© 


17 


139 


255 


221 


32040 


25 


33 


224 


90 


32044 


14 


32 


56 


177 


32048 


92 


214 


192 


48 


^^052 


2 


19c 


kW-. 


s ^ 


32056 


22 


8 


167 


237 


32060 


66 


146 


46 


251 


32064 


130 


9 


229 


123 


32068 


33 


224. 


87 


a© 


32072 


14 


64 


237 


82 


32076 


145 


48 


251 


129 


32080 


25 


14 


32 


30 


32084 


9 


29 


237 


66 


32088 


146 


4© 


250 


130 


32092 


9 


184 


40 


5 


32096 


21 


37 


61 


32 


32100 


251 


5© 


176 


92 


32104 


184 


40 


12 


193 


32108 


35 


3 


214 


6 


32112 


48 


250 


198 


6 


32116 


43 


11 


197 


79 


32120 


6 


6 


197 


213 


32124 


229 


121 


221 


70 


32128 


124 


14 





©6 


32132 


35 


94 


221 


102 


32136 


132 


10C 


185 


40 


32140 


15 


203 


56 


203 


32144 


25 


203 


60 


203 


32148 


29 


203 


35 


203 


321B2 


1© 


©1 


32 


241 


32156 


229 


33 


126 


92 


32160 


203 


94 


32 


12 


32164 


184 


40 


2 


203 



List remedy 



Robert Pearlman, 
Winchmore Hill, 
London. 



The list routine provided by Sinclair in ihc 
ZX-81 ROM is inadequate for the serious 
programmer for several reasons: a long 
Dfograra must be listed in small sections using 



many List statements, which is time- 
consuming and leads lo mistakes; the end of a 
very long line cannot be listed; after a Newline 
character in a line, which is common in 
machine-code programs, the rest of the line 
and the rest of the program arc sometimes not 
listed. Finally, after a ChrS 126, a common 
character in machine-code programs, the next 
five bytes are not listed. 

These faults are remedied by my List 
routine. When executed, a screenful of text is 
scrolled up the screen and displayed* A small 



black square then appears in the bottom left of 
the screen indicating that the program is 
waiting for a key to be pressed, either Break to 
abort the listing, or any other key to continue. 
The machine-code routine occupies 160 
bytes and may be located anywhere in RAM 
because it uses no absolute addressing, a good 
place being in RAMtop or in a Rem statement. 
It can be entered using any of the hexadecimal 
loaders that have been in previous issues of 
Your Computer, It is executed by Rand Usr 
followed by the start address. 



dh04. -^ h<>*>: 
0000 161S 

0002 DS 

0003 010014 
OOO^ CDFS06 

0009 217040 
OOOC 46 
OOOD 23 
OOOe 4E 
OOOF CO<*»OA 
0012 OJ 
OOlv IE16 

0015 DS 

0016 23 

0017 4A 

0010 05 
0019 23 
OOIA 23 
OOIB PF 
00 tC 20E£ 
OOIE 7E 
00 IF FOE 
0021 2009 

0023 70 

0024 01 0300 
0027 09 
0026 91 

0029 47 
O02A IBOC 
002C CD77 
002E F5 
002F CS 

0030 C44B09 

0033 CI 

0034 Fi 

0035 CCIOOO 

0038 23 

0039 3A3A40 
003C FE03 
0O3E 2051 
iXi40 01 

0041 15 

0042 10 

0043 AF 

0044 GA 

0045 2003 

0047 53 

0048 1E22 



CGKftf li-St 



CCHMlvnt 



Iprint *t b,c (20, OJ 



Ifirint Iiii# no. 



(b 1« lentiih of lint -1 



LD D.2I 
PUSH DE 
LD GC,5I20 

CALL 2293 
LD HL» 16509 
MLiLD B, <HL» 

INC HL 
LD Q, <KL) 
CALL 2712 
POP' OC 
LO E,22 
PUSH OE 

INC HL 
LD H. 1HL) 

Dcc e 

INC HL 

INC It. 

XQf% A 
NCULlNEtJR NZ. NL 
START.- LD A, (HL> 

CP 126 

JR NZ, NOT. 126 

LD AfB 

LD BC,5 

ADD ^tt..8C 

SUB A,C 

LD B»A 

JR SKIP 
N(IT.126i81T ii,A 

PUSH AF 

PUSH BC 

CALL NZ, 2379 s«:<p»adft chr«(a} 

PQ^ DC 

PO^ AF 

CALL 2. 16 ;prints chr«<*} 
SKIPt If*C HL 

LD A. (16442) 

CP ^ 

JR NZ. N06CR0LL 

POP DC 

DCC D 

DCC C 

XOR A 

CP D ;««B if A p«u«« i« n««d«d 

JR NZ, HISS 

LO D.E 

LD E,34 



tjump ov«r 5 byt#» of d«t« 



\%mm if chr«(«l i« prlot*l»li 



004A 
0046 
004C 
004D 
004F 
0052 
OOSS 
0036 
0057 
0O59 
005C 
005F 
0060 
0042 
0063 
0O66 
0067 
0068 
006A 
006B 
OO60 
0070 
0071 
0074 
0075 
0076 
0079 
007B 
007C 
0O7E 
007F 
OOOO 

oocr 
ooes 

0066 

ooea 

0069 

ooeA 
ooec 

OOBF 
0090 
0091 
0093 
0095 
0096 
0097 
0098 
009A 
009C 
U09D 



D5 

C5 

E5 

201 E 

2A0C40 

UF802 

19 

E5 

5680 

2A2540 

117FFD 

A7 

EDS2 

19 

CCOSOO 

OC 

24 

2aEF 

El 

360O 

2A0C40 

E5 

112100 

19 

Dl 

0iBSO2 

ED&O 

AF 

0620 

13 

12 

lOFC 

3A3940 

4F 

3E21 

91 

4F 

0614 

COF509 

El 

Ct 

loes 

3E76 

07 

23 

7E 

FE76 

2080 

Dl 

C9 



I if br»«k pr«s»»d th»n 
f output mrror cod* D 

th«lt prc^ram until k«y prmmmmd 



.^ISStPU&H DC 
PUSH SC 
PUSH NL 

JR NZ, NOPAUSC 
LD ML. < 163961 
LD D£,760 

ADD HL.OE taddro«a for 23,0 

PUSH HL 

LD <HL}»120 ipririt an lnver«o %pMcm 
PAUSesLD ML, a642U n«st kmy 

LD DEf 64895 tcods for 'brtfJik* 
AHO A 
SBC HL.DC 
ADD HC.DE 
CALL 2,8 
DCFB 12 
INC H 

JR 2, PAUSE 
POP HL 
LD (HLJpO 
NOPAUSEiLD Vi.» (16396) 
PUSH ML 
LD DE,35 
ADD HL.DE 
POP D€ 
LD 8C.693 
LOIR 
XOR A 
LD B,32 
LCKSPj IKC DC 

UD {D£},A 
OJNZ L0C3P 
LD A, < 16441) 
LD C,A 
LD A, 33 
SUB A,C 
LD C.A 
LD B,20 
CALL 2293 
PCP HL 
POP »C 
NOSCROLLiDJNZ START 
LD A«110 
RST 16 
INC HL 
LD A. (KL) 

CP lie 

JR NZ. NEWLINE :if #nd of pro^r^a thon return to BASIC 

POP DE 
RET 



l«croll 



I in* 



; print «t 20,0 



Sprite write 



Keith Berry, 
Birmingham. 




This program is a utility for redesigning 
characters or players — sprites — without the 
need for graph paper. 



100 Ren PuPyER/CHWPCTER DESIGN UTILITV 

ne REH i.t> Keah Berr^ i^zz 

120 Om Rf< 15 ):R$= "PRESS RETURN " 

l|e nPRSET=480: CHST=71 0: 6R3=650: 6R=370; C 

LS=S40:Ln=8£:HHl=12:8LU=ll2:Cl = i:C2=2:C3 

*3:C6«6:CX6«ie;20=B 

4^*1 LKP«764: C0ft»752i CR©=708 : Cft 1 ^7d9: CR2- 
710:CR4«712:©R*^HICS 20:POKE CR2,eLU:P0K 
E CRl,HHI:ROKe CUft*Cl:PO»CE Un,C2 

J.5®n£^nil?i,in=?S5=I ^BIMflRV REPRESENTftTI 
ON OF DECinflL NOS."i? ,*Xc> K. Serr^y 133 

lea POSITION 3*11:? -00 wu hant instruc 



TIONS'^" 

170 Z^Pttrv<LKP)SlF 2=efi THEN 170 

180 POKE LKP^en: IF 2=35 THEN eOTO SR 

I9y tiRflPHiCS £0: POKE. CRl^Cai POKE C«2#HH1 

:P0KE CUR^Ul 

200 ^ :^ '*PAay«ri> for PLAYER-niSSILE 6ftfl 

PHICS orCKar aethers in a rc<i€t!n€^d Charac 

t«r set arc construct*^ »n rgws o" 

210 ? "eVTES each 8 t>i^^ »idc. Each bit 

1^ tKrrfie^ on or not according to the n, 
o, that the byte hoids^." 
278 ? 

(continued on next page) 



YOUR COMPUTER, MARCH 1983 135 



soFrwfUKErttx. 



(continued from previous page) 

288 '^ "Oest-sn-s can &^ planned on 9*"^PH p 
aper,d<idin9 each bit to obta»n the decim 
ai" 

290 ? "number for each byte, but node 2 
of^^ this pro^ra** saves you thif trouble 

306 ? "flode 1 illouis you to enter deciAa 
1 dat^ and sec tK« result in9 c^aracte 

310 ? *'ln tK« case of a player, you can 
see the effects- ot increasing its widt.h 
to *' ; 

32© ? "to double or quadr»jpie Size as al 

lowedby Player-rtiSSi le graphics." 

33*i> -' 

340 ? ,HSi 

35e i:=j^eEK<u<p>;iF 2<>nhi then 350 

3S0 POKE LKP &M 

400 2=P€EK<LKP>:ir 2O30 fiNO 2031 THEN 

400 

410 KUKt LKP,ty'UIF Z=30 THEN GOTO 6ft3 
420 ? CHR*CCS>i-HOW nftHV Ll»CS" *: INPUT L 
430 ^ t^HPMCS} 
440 ■ ^^ENTER '^iLi'' NUieEftS C0 TO 255>":? 

450 Din Xt.L) 

^l?.^9? 9"^^ ^*^ *-*^ ^'''' "'-INPUT e:X<A> 

4?0 -> :y "HlOrH <l,^ or 4>-^i INPUT R: IF 



R<C1 OR R>2 t»MD R04 THEN 470 

480 POKE Ln,l5-ft*C3 

^iLf'^^S^^ Z02POKE CR1,C2:P0KE CR2,h*Hl 

500 FOR rt=Cl (0 L 

510 N=XCft>;naX(.fi> 

520 Z=l^^:C=Z0 

530 C=C+C1:IF C-S THEN GOTO 560 

III ftEn THE t iH THE MEXT LINE IS ftH INU 

540 IF n>=2 THEN FOR P^Cl TO R: ^ "*"i;NE 
XT P:n^tt-Z:2«2/C2:60TO 53u ♦ '-"^ 
550 FOR P=Cl ro R:?," '*;:Ntxr ps2-2/C2s6 

5SI3 '/*• '*;H 

570 NEXT ft:-^ 

530 '^ "CI^5Ni5E WIDTH <i,2 or 4>" 

V. ^^ I I HtN ^yy 

600 POKE LKP,Bn:lF 2=31 THEN R=Cl 

610 IF 2=30 THEN R=C2 

&20 IF 2=26 THEN ft=C3 

63© IF 2*24 THEN R=4 

B40 GOTO IIARSET 

•^50 GRAPHICS C3:P0KE CR0>22:POKE CRl,HHI 
:POtCE CR2*BLU:P0K£ CR4,20e ^I'Wi^ 

^^JS!5^ m^''^!'? "ORHH VOOR DESIGN IN TH 
^ f^l.'Ji^?.'^'^ flRROHS, SPflCE , DELETE 

4* RETURN, 

690 Puke CUR,C1:> -^No Shifts needed>. M 

^^cXS^ScrRPJ.^^.^^ COMPLETE/ PRES^. STAR 
T FOR RePDOUT,**i 

700 X=16:Y=C1 



710 IF PEEKC 53279 >^=C6 THEN SOTO CLS 

720 2-PEEKaKP>:lF 2<>Ce ftNO 207 RND 2< 

730 POKE 53279,20 

740 IF 2=HHI THEN X=l6sY=V+U IF V>16 THE 

N V— IS 

750 IF 2=a> IHEN X^^X-ClUF X<Cl6 THEN X= 
CI 6 

rm IF 2«7 IHEN X=sX+Ci:lF X>23 THEN X=23 
77^ IF 2=14 THEN V=V-ClUF V<Cl THEN V=C 

W^ IF 2«lD imEn y«V+C1UF V;^16 THEN V=l 

?3%? IF ^s33 THEN COLOR C3;PL0T X,V 

800 IF 2*52 THEN COLOR C2:PL0T X*Y 

810 FUR H=t:i ro Zu:NEXT H 

820 IF PEEKt 53279 >=e THEN SOTO CLS 

830 POKE LKP,Bn:60rO CHST 

840 ? CHRSCCS> 

850 Oiri XU6> 

860 J=128iK^Cie 

870 FOR R^Cl rO IS:X<A>»20:J=128 

880 FOR K«C16 TO 23 

890 LQCHIE K,ft,p:|F P=C3 THEN XCfi>*X<AH 

i*00 IF ^^k:^ I hen j=a-/C2 

910 NEXT -K 

920 NEXT A 

930 ^ "THE DftfA FOfi THIS DESIGN:" 

940^FOft ««C1 TO 16:? X^l^ >;",%: NEXT fi: '^ 

950 ? R*; 

9S0 2=PEEK<LKP>:IF 20HHI THEN 960 

970 POKE LKP,emR^C^:L=l6:GRI^PHICS 20: PO 

K£ tRl,C2:P0K£ CR2,WHI:G0T0 HARSET 




Auto-list 

5 M Russell, 

Lee, 

London. 



It is somktimes useful to list part of a 
program automatically under the control of 
that program. For example, a program could 
give the option of changing the coniems of its 
Data statements, and then list the relevant 
lines for alteration. Unfortunately* BBC Basic 
does not allow the use of the List command 



within a program. These subroutines over- 
come the problem. 

ProcList scans the program in memory and, 
when it finds the required lines, sends each 
line number, its position in memory, and the 
line length to ProcDccodc. ProcDecode first 
prints the line number, and then sends each 
byte of the line to a resident routine — located 
at &B53A — to be translated into a keyword if 
a token, or into ASCII if not. The result is 
then printed. 

There is one limitation that ProcDecode 
does not translate the Une numbers associated 



with Goto and Gosub correctly, because these 
use a special code. 

When calling ProcList, the two parameters 
in brackets after the procedure name specify 
the first and last lines to be listed. If only one 
line is required, then set both parameters to 
that value. Line 10020 gives a demonstration. 

These procedures may also be used in error- 
trapping routines, to display the offending line 
automatically; for example: 

10 ON ERROR GOTO 10035 
10035 MODE 7:REP0RT:PRINT:PR0Clisi 
(ERL,ERL):END 



lOOOO REM SUBROUTINE TO LIST FROM WITHIN A PROGRAM (C> S.M.Russell 1983 

lOOlO REM DEMO 

10020 PROClist (10040, 10120) 

10030 END 

10040 DEF PROClist (nl,n2> 

10050 LOCAL length-/., line„no%,start7. 

10060 startX=PASE;e7.=5 

10070 REPEAT 

lOOaO 1 ine_noy.===start%?l*256+start7.?2: I©ngth7.=start7.?3 

lOO^O IF line_no%>=nl AND 1 ine„no:C<=n2 THEN PROCdecoded ine_noX, start/-, lengthy. 

) 

lOlOO start7.=start7.+Iength7. 

lOllO UNTIL start7.?l=8<FFse7.=8<AOA 

10120 ENDPROC 

10130 DEF PROCdecode(line_no7.,start%,length7.> 

10140 LOCAL AX, 1% 

10150 DEC0DE=&B53As I7.=4 

10160 PRINTline_no7.; 

10170 REPEAT: A7.=start7.?I7.: CALL DECODE 

10180 I7.^I%H"1: UNTIL I7.=length7.: PRINT 

10190 ENDPROC 



Status 



mmmm 



Colin Carruthers, 
Edinburgh, 

This program was written on a 16K machine 
and will run in either 16K or 48K. It is a short 
three-line program which I called Status. 
When execiued it returns a number of useful 
pieces of information about the general status 
of the machine — program size, variable space 
and free space. I use it while developing other 
programs. 



a oep FN pfn>=PEEK n+-^5:e*PEEK 
I n + 1 > 

99«@ Cl-S . OR^^UI SSS^ia. DRAW Ci/.a7 
S; DRRU -25S.CI: ^^f^U e ^ - 1 7S . Pi_0 
T 4.0^15:8: DrAu 137, €»; PRINT HT 1 

^5; "Machine sst a t u5^ - * "; j^t 4.^£; -to 
Id I RflM : '; CFW P f^3T-3:^> -:i©3 

ea.v yice*; •* k";bt 6,2, "Hi crodf i ve 
iiaps,";FN p r23e3l,i -a373*; ' bt/te 
s *;rt 7,s;rt at^2;"BRSXC pro9rd» 

•*; FN p f^36S7> -FN p f23e3S> ; " by 
tcs";RT ^.. S; "Uir i ab tes :";P 

N p ca3&4.Ji.> 'FN p f:23eS7'> -J.; " byte£ 
";^T ia,2;'Pree space^ ;";FN 

p t237'30> ~rH P fS3e4>l-* ; *' bt^ttJ^'^RT 
a0^2; '*UDG;. ReiCDE:FCHX^tKI.MNORORSTU 

@9SI$ PRXNT RT a4.,2;"Urp Ti »e 

. ".. INT < <^H p fS3e7Sit -»es53e^pe 

^K S3©74.> ^SO) ; " J^rconds". GO TO 
9S99 



MacHine 


3t,*tUA« . 


Total R«rt 




.*4^ K 


Hi crodr ivc 


Hftps 


; B b««t«» 


Uariabi«s 


: 3^177 b^tes 
.73 bS»t«A 


Fr«« Sp*ce 




. ::»ee£4. b^t«» 


Uf* Ti»« 




; leo i^«can<is 


UDG: AQi^«CFC3^XUKI.HNOPQR*IOU 



1 36 YOUR COMPUTER, MARCH 1 983 




The wall 

Robert O'Donnell, 

Stockport, 

Cheshire, 

The object of the game, which takes under 

16K of RAM, is to catch 10 of the apples that 

arc being thrown over the orchard walL You 

steer the basket at the bottom of the screen 

using keys 5 and 8. 

20 16 graphics shift A 

SO 16 inverse L 

80 inverse L; graphics shift 8; two inverse 
spaces; graphics shift 5; inverse L 

90 inverse L; four graphics shift 6; inverse L 
3000 inverse L 
3020 inverse star 
9610 as line 9600 but inverse. 

Fronn the screen 



SOfTWmSFHJE. 



m^mmmmn^m- 



10 FOR lal TO Ag 

*» FOR 1=1 TO 3* 

CS NCXi jl 

ei POKE 164-ie^X 

Se PRINT "SCORE O" 

70 LET BflTaJ 

dO LET A$a"i 

90 LET 8$a'_ 

Ide LET ^CORcj 

XSe LET PPPLE5S0 

X30 QOSUB 2030 

14.e GOTO 9000 

X000 PftXNT RT 20,Bf4T;l^»; PIT 2X,SPI 

l6x0 LET e«T«BPT+(IiS|KEy»*'*3"J - (I 
NKCy» = "S'*) 

X0a0 LET BfiT-SrtT- <BAT«a7J *•iBRT-- 
X> 

1030 RETURr4 

2O0O LET RPPLeV-flPPLCV^a 

301© IF RPPLEY<S0 THEN RETURN 

2020 IF flPPLEX=BRT+3 OR APPLSXaB 

«T+2 THEN LET SCORE -SCORE +1 

SO30 LET RPPLEX=1NT (RND*aS+aj 

20*0 LET RPPLEY=5 

2045 PR II tT RT 22 ^ ft; SCORE 

2047 XF SCORE =10 THEN GOTO 9500 



S04te LET RPPLes«iRPPLeS-l>X 

2049 PRINT RT £2 , IS; "NUMBER : - ; R 
PPLES 

2050 RETURN 

3000 PRINT RT RPPLEY , RPPLEX; "H* 

30X0 GOSUB 200O 

3020 PRINT RT RPPLEY , RPPLCX; "B'* 

3030 RETURN 

9000 GOSUB 100O 

90X0 GOSUB 3000 

9020 GOTO 9000 

9SO0 LET R»»"UeLL OONE ^ YOU MRUE 

CRUGHT TEN- * 
9SX0 FOR I=X TO 32 
9520 FOR U>e TO A 
9530 PRINT RT U,I-X;R$(I> 
9S4.0 NEXT U 
9S50 NEXT I 
9560 LET Rf=" MOUEUER YOU UftSTCD 

'+STR» (RPPLES-10> +'• RPPLE5 " 
9570 DIH B^CLEN R$> 
9SS0 LET XalS-LCN Rf^2 
9S90 PRINT RT XX,X;B«;RT 13,X,B» 
• la-f- 1 Q X R A 

9600 p6xnT RT 22,0; "PRESS NEULIN 
E FOR RNDTHER GRME . " 
L0 PRINT RT 22 ^0; 



120 IF INKEYfw" 
9630 CLS 
Sft40 RUN 



rHEN GOTO 9600 



Nige/ Beasley, 

Exeter, 

Devort, 

This program is an assembly language 
program for a Model B BBC Micro with a 
printer imerface and Epson MX-80 F/T 3 
printer or similar. The fmal' routine occupies 
about 250 bytes and is located ai 10000 in the 
memory. Alterations may have to be made for 
other printers. This program takes about two 
minutes to print the entire screen, much faster 
than any Basic program. 
In this way, graphics and text 



can be reproduced at the same time. 

To use the program, type it in exactly as 
shown, leaving out any comments, if you 
wish. Comments follow an oblique sign. Run 
the program. If you are sure that no errors 
have occurred then type: 

*SAVE"DUMP" 2710 2803 (Return) 
This saves the area of memory where the 
program occurs. Also save the assembly 
language program as usual: 

SAVE"ASSEMBL" (Retum) 

To use the routine in your programs simply 
use the Basic command; 

CALL 10000 

10000 is the memor)' location where the 
routine starts. When using the program it 



must be ensured that you do not overwrite it 
with a Basic program: Top must be below 
10000. To reload the routine into memory 
having saved it under a particular filename use 
the command 

*LOAD"DUMP" 2710 

When reloading the program it will not 
disrupt any program already in memory, so it 
can be loaded into memory from a Basic 
program, using the aforementioned command. 

To use with another printer; it must be a 
dot-matrix printer with bit image printing 
capabilities. The areas where specific 
commands for the Epson are shown and the 
commands for your printer can be inserted 
here. 



10 
20 
30 
40 
50 
60 
70 
80 
90 
lOO 

no 

120 
130 
140 
ISO 
160 
170 
180 
190 
200 
210 
220 
230 
240 
250 
260 
270 
280 
290 
300 
310 
320 
330 
340 
350 
360 
370 
380 
390 
400 
410 
420 
430 
440 
450 
460 
470 
480 



R01 A«s«4ibly languagw pregraa to du«p wcrmmn onto printer 490 

REM For EPSON HX-80 F/T 3 5O0 

REM (c) N.8*A«l*y 23/1/83 510 

CLS 520 

OS«ORD*lcFFFl 530 

OSWRCH»«cFFE£ 540 

PX-lOOOOi REM Smtm progrui counter ♦•DO NOT Om48€ ! ! !•* 550 

I 560 

LOA £2iJdR OSWRCH \ Turns on printvr 370 

LDA £ltJ8R OStiRCK \ 8«ts th» lln* spacing to 1/32 inch 580 

LDA £27iJ8R OS*iRCH \ on *n Epson 5^0 

LDA CliJSR OSWRCH 600 

LDA C5liJSR OSWRCH 610 

LOA iritJSR OSWRCH 620 

LDA £24tJSR OSMRCH 630 

LDA CSilF \ Inltialis«« Y valu* 640 

STA hi? 650 

LDA £4 660 

9TA l«78 670 

CLC \ Start of «Aln loop 680 

LDA If 77 \ Subtracts 32 4rom Y vslu* 690 

SBC £31 7O0 

STA Ic77 710 

LDA t<78 720 

SBC £0 730 

STA «(78 740 

LDA £lf JSB OS4#%CH \ Puts th» Epson printer into 750 

LDA £27iJSR OSWRCH \ 'Bit l4Mgs printing' «od« 760 

LDA £ltJSR OSWRCH 770 

LDA £76tJSR OSWRCH 780 

LDA £ltJSR OSWRCH 790 

LDA £128tJSR OSWRCH 8O0 

LDA £liJSR OSWRCH 810 

LDA £2rJSR OSWRCH 820 

LDA £S.FF \ Initialsss X valus S30 

STA 1.70 S40 

LDA £«(FF 050 

STA Ic71 ©60 

.XCOOD \ Start of Xcood loop B70 

CLC eso 

LDA ir70 \ Adds 2 to X valu* 89C> 

ADC £2 900 

STA *(70 910 

LDA 1.71 920 

ADC £0 930 

STA 1,71 940 

LDA £252 \ InitiasM Y AOVMMnt valus 9SO 

STA 1(75 960 



LDA £0 \ Initialisas mmmory loacation to racaiva 'bit laags* 

STA t(79 

.YCOORD \ Start of aaarch 

CLC 

LDA &7S \ Adds 2 to Y saarch valu« 

ADC £4 

8TA ItTS 

LDA Ii77 \ Rut actual Ycood valua into position raady for call 

SBC «<75 

STA 1(72 

LDA 1(78 

SBC £0 

STA 1*73 

LDA£9 V Sats A«9 for OSWORD call 

LDX £lf70 \ Points to locaton of a aa o ry Mhara ccxirds mrm hald 

LOY £0 

J8R OSWORD 

CLC 

\ Takas prasant 'Bit laaga* 

Rotatas it laft 

V Adds rasult of OSWORD call 

N Storas rasult 

\ Branchas back If not finlshad 



Sands rasult to printmr 



LDA 1.79 

ROL A V 

ADC If74 

STA 8.79 

LDA £27 

CMP <<75 

BPL YCOORD 

LDA £ltJSR OSWRCH \ 

LDA S.79IJSR OSWRCH 

LDA Ct^f \ Branchas back to Xnzrm^^mm X valua If not 1279 

CMP «.70 

SHE XCOOD 

LDA £4 

CMP tt71 

&iE XCOOD 

LDA £l£JSR OSWRCH \ Sands linafaad to printar 

LDA £10iJSR OSWRCH 

LDA <i78 \ Branchas back to dacraasa Y valua If not 

BNE ^2800 

LDA £31 

CMP S<77 

BNE Sc280O 

LDA £3 \ Turns off printar 

JSR OSWRCH 

RTS 

7 

PX-t(2800 

C 

J MP St273B 

3 



Decimal liner 



WB^ 



KWHalh 

Catterick Garrison, 

North Yorkshire. 

This useful subroutine was written for the 

Vic-20 but can easily be modified for other 



micros. Anyone who writes programs and 
requires their outputs listed in columns will 
know that Basic does not line up decimal 
points. The following subroutine docs just 
that. The subroutine expects the variables to 
be processed in X: the output is in X$, 
8000 A$ = RIGHT$(" " + STR$(INT(X)14) 



8030 B$=LEFT$|MID$(STR$(INT((X-INT(X)) 

M00 + .005)) + "00",2I,2) 
8040 C$ = ".":X$^A$ + C$ + B$:RETURN 

X string can now be Printed in a normal For 
loop Print routine. The spaces in line 8000 
can be increased to adjust the position of the 
output on the screen. H 



YOUR COMPUTER, MARCH 1 983 1 37 




OPERATING AND CONTROL SYSTEMS FOR 
DISCERNING SPECTRUM AND ZX81 USERS 

All Amsoft products are designed to help users to get the most out of their machines. No additional hardware is 
needed to run them, but they can be used to support other devices if needed. 

Am-ZX FILE is a system which allows you to use large cassette data files in BASIC programs. There is no limit to 
how much data you can store or retrieve. Gives tape facilities like a large machine* ZX81 version £4.00, Spectrum 
version £5.00. 

AM-ZXMON is the ultimate operating system. With it you can create, edit, run and checkpoint machine code 
programs, and can save, load and merge portions of programs to or from tape. You can build and use your own 
subroutine libraries. ZX81 version £6.00, Spectrum version £7.00. 

Under the control of AM-ZXMON you can run, AM-ZXEDIT, the text editor which allows you to produce source 
tape files for input to the AMAZON assembler. An easy-to-use product with exceptional facilities including tape 
merging and renumbering, are ZX81 and Spectrum versions £4.00. 

Am-AZON, a full two pass assembler which converts assembler source tapes created by AM-ZXEDIT into 
machine code tapes which can be loaded and run by AM-ZXMON. All ZX80 op. codes are recognised. Symbols 
can be up to 5 characters and symbolic, hex, string, or decimal are permitted. ZX81 version £8.00, Spectrum version 
available end of March £9.00. 

AMERSHAM SOFTWARE LTD. 
Long Roof, Nervines Road, Amersham, Bucks HP6 5HS 

Tel. (024 03) 6231 



IF YOU WANT: 

*The Latest News on the BBC Micro 
*Top Quality Programs 
*Useful Hints and Tips 

* Honest Reviews 
*lndependent Opinions 
*Locai User Group Information 

* Members Special Offers 



THEN YOU NEED: 




The Newsletter of the Independent National BBC Microcomputer 
User Group* 

MEMBERSHIP: £12 for 1 year (£15 overseas) or send £1 and an A4 
size SAE for a sample copy. 



Write to. 



LASERBUG, 10 Dawley Ride, 
Colnbrook, Slough, Berks., SL3 OQH 

Memb«r8 m 14 Countries WorWwide 



PASCAL FOR THE 
ZX SPECTRUM 

Hisoft are pleased to announce the availability of Hisoft Pascal 4 
for the 48K ZX SPECTRUM. 

No tonger do you have to put up with the slow execution speed of 
BASIC programs; Hisoft Pascal 4 produces programs that run 
between 40 and 100 (yes 1001) times faster than the equivalent 
programs written in 2X SPECTRUM BASIC. For example, a 
program to sort a 100 element array of numbers into ascending 
order takes 60 seconds in BASIC, while HP4 produces a program 
which does the same thing in 0.6 seconds*. 

NOW you and your children can learn to program fn an efficient 
and structured way by using Pascal, the favoured language in 
schools and universities. 

NOW you can write games programs etc. which run as fast as you 
need them to without having to resort to assembler or machine 
code. 

NOW you can use a language which requires minimal re*learning 
when you move from your SPECTRUM to another computer; 
Hisoft Pascal 4 has all the essential features of Standard Pascal as 
detailed in the Pascal User Manual and Report — by Kathleen 
Jensen and Niklaus Wirth, the man who designed Pascal. 

Hisoft Pascal 4 is a professional piece of software designed by a 
team who have been writing Pascal compilers for many years — 
you will find it to be powerful, flexible and very easy to use. 

To top it all, we are offering the package iwhich includes a 60 page 
manual), for a limited time, to 48K ZX SPECTRUM users at an 
INCREDIBLE price of; 

ONLY £25 INCLUSIVE 

Write for more details TOD A Y to: 

MHISDFT 

60 Hallam Moor 
Liden SWINDON 
SN3 6LS 

Tef. (0793) 26616 (Answering machine) 




138 YOUR COMPUTER, MARCH 1983 



cmpsmmi coRNea 



A £15 book token will be awarded to the first correct solution 
drawn from the competition bag. All entries must be at the 
Your Computer offices by the last working day in March. The 
name of the winner, the solution, and a competition report will 
be published in the May, 1983 issue of Your Computer. 

If you want to set a competition for Competition Corner, 
remember that the simplest solution should be calculable by a 
short program rather than by any other form of reckoning. 

TELEPATHIC DANGERS 



BY ANTHONY 



ROBERTS 



You HAVE found the fabulous cube of On'ey! 
Howcvctj as you approach, a careless thought 
triggers a circuit, and the cube tumbles apart 
into six regular squarc-based pyramids, and 
you know that you have just minutes to re- 
construct it before the segments crumble to 
dust. Each segment connects to its 
neighbouring segments via a set of four lugs 
and four holes, two to each triangular face — 
each lug must match a hole on the next 
segment. As you gather the segments you 
notice that there are in fact the eight segments 
shown here; connect either of the extra 
segments to any of the original, and you will 
probably lose your life. Which two segments 
should you discard? 




COMPETITION 
RESULTS AND 

jANUARrS COMPETITION to win an Oric 
asked cont^tants to complete the crossword 
and the sentence, **My New Year shouid start 
with an Oric because . , .*\ If the number of 
entries for our competitions is any indication 
of how popular a new computer will be, the 
Oric shouid do well; but not as well perhaps as 
its closest rival, the Spectrum, which drew 
several hundred more entries last July. 

The winning entry was a rather off-beat one 
from J Elliot, I Saint Mary's Road, Burgess 
Hill, West Sussex, who wrote **I got those 
ZX'81 - 16K - RAiM-pack - wobble 
blues!". Unlike the ZX-81 the Oric, of course, 
keeps its memory tucked away inside the case. 
The ZX-81 also came in for a bit of stick from 
R Booth who said that **the Alsatian keeps 
mistaking my ZX-Sl for a dog biscuit**. 

Quite a few readers showed their learning by 
making a play on the line from Hamlet, **Alas 
poor Yorick. . /*, The best of these was P 
Douthwaite*s **Alas poor Oric, Vd use him 
well, a computer of infinite jest". This is the 
one quote, incidentally, that everyone gets 
wrong. Look up your Hamlet and you will see 
that Hamlet says not, "I knew him well" but 
"I knew him Horatio". Neither version, 
however, is particularly relevant to the Oric. 

N Dickason claimed optimistically that 
**with my Oric promotion will be meteoric'% 
while S Yeo revealed **my wife has run off 
with the Sinclair". From A Cutler came "it 
w^ould provide the Basic necessities for life . . , 
and many other games". 

Finally, G Towner's entry raised the big 



WINNERS 



question hanging over Oric International — 
can it deliver? He pointed out that his New 
year should start with an Oric because "it will 
be over 28 days since I ordered one". 

A number of correct solutions were sent in 
for the Star Stone competition but few were 
accompanied by a program. Admittedly the 
problem did not lend itself to a short program 
solution. To find the answer vou needed to 



work out that there are only three faces on the 
Stella Octangular which cannot form part of a 
closed loop. Between them they contain one 
tetrahedroid crystal, three pan-metallic 
hypcrcubes and five spheroid diamonds. 

The £15 book token goes to the first correct 
entry picked from the bag which was from P 
Carlotti, Hope Paint House, Granville Road, 
Kingsdown, Deal, Kent. ■ 



The solution to January's 
crossword when a prize of 
an Oric 7 was at stake. 
Although swarms of 
aspiring Oric owners 
came forward, the level of 
entries failed to match last 
July's competition with 
its prize of a Spectrum, 



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^^mmmam ^m 



YOUR COMPUTER, MARCH 1983 139 



NEW - ORIC - ORIC - ORIC 
SPECTRUM - ZX81 
SEVERN SOFTWARE 



•GRAIL 

OMC 16K&4$K £4 $6 MC 
SPfCTftVM 1€K(f46K C4.$$ tNC 
2X$t 1$K€49StfiC 

Exciting graphic adventure set in the 

Castle Perilous* Where m the 1,000 

rooms Is the HOLY GRAIL? 

Gather armouf and weapons to fight 

Dragons, Ores and Wolves. Find gold 

and Precious Stones to buy strength 

potions from a Trader. Stairways to all 

10 levels. 

Where will the Warp take you to? 

If you tose, you can watch yourself 

bleed to death! 

Full M/C Sound Effects and Save Game 

facility. 



•ROADRUNNER 

OfiK J$tC &4Sf(£4m iNC. 
St*£CrfiUM 1$K&48K £4S6 WC 
ZX$t t6K C4,$6 WC 

Everyday from Monday to Friday Mr, 
McGoo gets in his car and drives hon>e 
from the office. Mr. Mcgoo is such a 
lousy driver that he'll crash into 
anything that gets in his wayl 
The roads are full of Mr. McGoos. Can 




you get homo from your office without 
becomrr^g one of their victims? 

•MORIA 

ofix f&(&4$K £4.$$ mc. 

SPECTRUM tSK & 4$K £4,$5 iNC. 

A challenging gfdphic adventure set in 
the Mines of Moria. Can you survive 
encounters with the Monsters of 
Middle- Earth: the Balrogs, the Ores, thv 
Trolls and the Wargs? Will the Wizard 
help you? Can you buy your safety from 
the Trader? Are you fated to die beside 
the seeled doors? Or have you the 
power to open them? 
Unless you find Ourms Ring you will 
never leave the Mines alive! 
A game to test your character. 
Full M/C Sound Effects and Save Game 
and Reset facilities. 
• ZX81 16K version £4.95 INC. 



Graphic display of Data arKt Regression 
lines. Saves named Data -files. 
Spectrum and ZX81 versions support 
ZX Printer. 

•THE M/ C MANUAL 

a.$6 WC 

Easy to use (can be used by the 
absolute beginner) . Fulty detailed guide 
to Z80 Op Codes and M/C 
Programming. Convenient A4 format. 
Fully docunwnted tables of Codes, 
Displacements and Number 
Conversions. Easy to follow diagranns 
and routines throughout. Designed to 
use not just to read. 



•Ask for SEVERN SOFTWARE 
at your local Computer Shop, 

•We guarantee to replace AT 
ONCE any cassette sold by us 
that fails to load on receipt. 



•The exact software specification 
varies fronn machine to machine 
particularly with regard to 
sound and graphics. 



•STATISTICS 

OfttC J6K&49K £4.$6 mC 
SPCCTPUM 16K&4$K £4.BS INC. 
ZX8J f6K £4$S INC 

Powerful Statistics package. Menu- 
driven. Features Means, Standard 
Deviations, True Linear Regression, 
Pearsons Coefficient of Correlation. 
Extensive Data Editing routines. Full 

PLEASE SEND ME.. 

(STATE MACHINE TYPEJ 

I ENCLOSE CHEQUE/P.O. FOR £.. 

NAME 

ADDRESS.... ..,. 



.,... POSTCODE.... 

SEVERN SOFTWARE 

5, SCHOOL CRESCENT, LYDNEY, 

GLOS GL15 5TA 




IGRA Pin. c:5;.,,>iADK IT^KSY m 



. 3 HT RES :i^ I ;a;xxej< s 



aval iable Wyr the 
T "DRACVnX 8 2 ; 
256 X 1 92 ;.\vi t h , chcir sq . ... 16 >< 32 

and (he ^ 

ZX SPECrRTTM 

266 >: 1 9 2 W i { 1 1 dlElr Hq 24 x 32 



""1m 



BO SHEE'r :FA:n 

LY £a-oa ijjc p*p 



" FAiST i>Ki;iy;itRy- 

please state wIhgIi conijniler 





. XAVil'BliiSTM^ 

in > SOME R XOiRlOii 
ATU A VOX BAB 2 



che<|ues jjayaWc Lp xaviqrsi Tie. 



140 YOUR COMPUTER. MARCH 1983 



SPECTRUM SPECTACULAR £4.95 



DRAGON EXTRAVAGANZA £4.95 



Two new books by Roger Valentine. Each containing 
a mammoth 50 programs (for the Sinclair Spectrum 
and Dragon 32 respectively). 

From the publishers of: 



WHAT CAN I DO WITH IK £4.95 



WHAT CAN I DO WITH 16K £4.95 



The two best program books for the Sinclair ZX81. 
A vailable from your bookshop, or 

V&H COMPUTEER SERVICES 

182c Kingston Road, Staines» Middx. 

Tel: Staines 58041 



BUSINESS USERS PLEASE NOTE: OUR PAYROLL 
PROGRAM IS NOW AVAILABLE FOR: ZX81, SPECTRUM, 
PEl, BBC, KONTRON AND SOON DRAGON PLEASE 
WRITE FOR DETAILS OR SEND £9.00 FOR 
COMPREHENSIVE MANUAL (SINCLAIR VERSIONS ONLY) 



I 




dUmanber 
dftwoxc 



Dragon and BBC 
Model B Software 



DRAGON 32 SOFTWARE 
DRAGONTREK C9.95 

A real time version of the classic space game featuring full colour Tactical, 
status and long-range scanner displays, hyperbole, the Faerie Queen, 
Klingons and Klingon comnrtanders. tractor beams, enemy movenneni, black 
boles and nrujch more. Choose from ten ievels of difficulty and three sizes of 
galaxy. Comes complete with S-page flight manual JOYSTICK (It 
REQUIRED, DRAGON DATA APPROVED. 

WIZARD WAR £7.95 

A game of magical combat between the Wizards of the Tri-Suns for 
supremacy of the planet Xarg. Both dexterity and deduction are needed in 
order to outwit your opponent as spelt is traded against spelt. Comes complete 
with 12-p39e illustrated spell book, JOYSTICKS (21 REQUIRED. DRAGON 
DATA APPROVED. 

GOLF f7.95 

An accurate interpretatfon of the game of golf wfitten by a keen club player. 
Allows match play between two players or one player nrwjy play using the 
Stableford points system widely used for competition golf. Features full club 
selection, hazards, out of bounds and player handicaps, DRAGON DATA 
APPROVED. 

GRAND PRIX D.95 

Do you have the potential to be a champion Formula 1 driver? Find out 
when you race on th^e 8 fanxjus Grand Prix tracks from around the world. 
For 1 and 2 players, 2 joysticks required. Dragon Data Approved, DRAGON 
DATA APPROVED. 



VULCAN NOUGHTS AND CROSSES C7.96 

A three- dimension game of noughts and crosses for one or two players. 
Also tnctudes a zero player option where the nr>achinc plays itself. Can you out* 
think your Dragon? DRAGON DATA APPROVED. 



BBC MODEL B SOFTWARE 
THE EDG GRAPHICS PACKAGE £24.95 

F(K the BBC ?^ode1 B Microcompijmr 

An advanced picture drawing system developed by a firm of consulting 
engineers to the oil and utility industries world-wide. Uses cassette tapes for 
software and picture storage and is controlled eniirely by normal keyboard 
input — no extra hardware required. The main system features are: 

• Picture drawing in mode 0, 1 or 2. 

• Actual and Logical colour changes at any time. 

• Drawing functions: 

Lines, boxes, circles, arcs, text, shape repetition 

• Drawing aids: 

Grid, elastic band, save and home cursor (5 posrtionsl 

• Colour fill. 

• Text window showing x,y cursor p<^it(on, length, angle, colour n>enu and 

currem colour. 

• Saving and Loading of picture usir>g cassette tapes, 

• Multi-file pictures facilitating very complex drawings. €' 

• Flashing cross-hairs cursor. 

• User instructions/prompts. 
This package comes complete with a spiral bound manual. 



GAMES COMPEfMDIUM D1 a.Sb 

Six great games for the whole family — Donkey Derby, Blackjack, 
Kingdom, Hunt the Wumpus, Noughts and Crosses and Lunar Lander. 
DRAGON DATA APPROVED. 

Send SAE for caiahgue of om full fBnge of Dragon and BBC Modd 8 Software 

Cheaues or postal orders payable to Salannander Software, 27 Ditchling Rise, 
Brighton, East Sussex BNT 4QL. Tel: 0273 771942, 

PLEASE ADD 50p P&P TO ALL ORDERS 

Programmers wanted: good royalties paid! 





PIMANIA 



THE ADVENTURE GAME THAT'S FOR REAL ! £6.000 PRIZE! 

Wilt YOU b« th« lint to tocai« the Gokton Suiyhat of n m iim« «nd si>M€. 4nd t»e 
few»rded with the ofi^fiaJ' Exquiindy crafifd by th» dinner of th* D« fteefi 
Dumood Inttrnjrlon^l Award, from gold, domond aod themoii p«eC40uio( the 
earih'inch« 

PtMANIA whfre u>cophor>« luin »f»to h*ogl»drfS, whete muiic meets n>*lncti 
a rx j whcfc the h M#n ruin su t> rcmg' Ht'H t jl k w i th you. he' lt bef f>en d yO g . ht'n 
betray voo. he'll even do the Hokey Kokey* Animated M*too*» »*ph»ct* FuU 
music*! fcoft' Spfct*cula« eokwr am] MKind *lfectt<* lAtfude* free hit tii^e 
"Pimani*". ^th vocali by Clair Sincltve *¥J ih« Pi M*^' 

It otMid t*M vow a wMit to play, it covid tafe* you a hfetim*^ PtMANIA, 
" th# betl mdanct thai cooipwttf naming has com* of age . an adventure 
enihosiMt'f dr^imT" (Computer * Video Gamei) 



48K SPECTRUM' 
I6K ZX8I 
DRAGON 32' 
BBC Model B* 



£10 
£5 
£10 
£10 



AUTOMATA Ltd. 
69a Osborne Road 
Portsmouth P05 3LR 
England 





BEAT THAT HIGH SCOREI 
GOBBLE THOSE DOTS 
BEFORE THOSE MEANIES 
GOBBLE YOU! YOUR ONLY 
AIDES ARE FOUR 'TOWER 
PILLS" WHICH MAKE THE 
MEANIES EDIBLE- BUT 
NOT FOR LONG! 

• MACHINE CODED FOR FAST ACTION 

• EXTRA ''GOBBLER" FOR 10,000 POINTS 

• ON SCREEN SCORING 

• HIGH SCORE WITH "ENTER NAME" FACILITY 
•up TO 4 PLAYERS 

AN ANNOYINGLY FRUSTRATING GAME! FOR ONLY £5.95 




STAY ALIVE AS LONG AS POSSIBLE IN OPEN SPACE FILLED WITH FLYING ROCKS 
SCORE BY SHOOTING THEM - WHICH ALSO CAUSES THEM TO BREAK INTO LOTS 
OF LITTLE BITS AND MAKES LIFE EVEN WOBSEI 



• machine COOtO FOR 
FAST ACTiON 

•on screen SCORING 

• high score with 

EMTER NAME FAClLtTY 

• up TO 4 PLAYERS 



•extra ship POR 1,000 PTS 
(NOT AS EASY AS IT 
SOUNDS 11 

• %H\P MOVES JUST LIKE 
ARCAOt VERSION 

• rotate LEFT/ROTATE 
RIGMT/TMRUST 



•fires IN AIL 8 
OtRECTiONS 

• INCREASING NUMBER 
OF ASTEROIDS 

• THREE ASTEROID SIZES 

• NASTY' ALIEN SPACE 
SHIPlFlRESBACKn 



THIS GAME IS JUST AS BAD! - AND ONLY £5.95 
AN OFFER FOR REAL MASOCHISTS-BOTH TAPES FOR £9.95 

MAIL ORDER ONLY-PLEASE MAKE CHEQUE/PO PAYABLE TO 

THE SOFTWARE FARM DEPT B 
CRAIGO FARM. BOTANY BAY. TINTERN, GWENT 



IV1MIU \. 



Sp 



YOUR COMPUTER, MARCH 1983 141 



BBC 'A' D BBC 'B' D ORIC D 



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Emmci] 



For the best selection of Micros 
for business: 




• Apple II, III 

• Commodore 8032, 8096. 

• Eagle II, III, IV, V. 

• Eagle 1600, 16 Bit. 

• 10TEC lona Colour. 



Used Business systems available, 
phone for details. 



£75 worth of Software 
Free with every MZ80A 




ATARI 




•• 



Free T Shirt with 
every ATARI 400 
•• Free Sweat Shirt with 
every ATARI 800 



SOFTWARE OFFER 



ATARI 

PREPPIE £21.95 
SHOOTING ARCADE £21 .95 
BUG-OFF £21.95 
PAC MAN £29.99 
SPACE INVADERS £29.99 

VIC 20 

JELLY MONSTERS £19.95 
ALIEN £7.95 
PIN BALL £24.95 
FROGGER £9,99 
BOSS £14.95 

TEXAS 

SOCCER £22.95 
CAR WARS £26.95 
MUNCHMAN £26.95 
Tl INVADER £18.95 
CONNECT 4 £22.95 



For nnore details tick on border and send with SAE 

Free PASE TShirt with every order of £50 placed in March 



BBC 'B' 

PASEMAN £7.00 
2AP0 £5.00 
PODS £5.00 
DRAGON RIDER £7.95 
TANKS £7.95 

SrNCLAIR 

PUCKMAN £5.95 
BUMPER 7 £5.95 
SPACE INVADERS £6.95 
CHESS £6.90 
PILOT £5.95 



> 

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213/215 Market Street, Hyde Cheshire 
Tel: 061 366 5935 Telex 665845 



LYNX D JUPITER ACE D DRAGON 32 □ 



SIR Computers Ltd 
CARDIFF 



Agents for Acorn, BBC and TORCH 
Computers 

BBC Microcomputers 

ModeM Awiih32KRAMandVIA, £33S.OO 

Model 1 A with 32K RAM, VIA and Joystick port £354.00 

Model B... ..., £399.00 

Model B with disc interface £509.00 

Single 100K disc drive. £249.00 

Dual 2 X 100K disc drive £389.00 

The disc manual and utilities disc are both included* 

Disc interface for the BBC Micro (kit) £95.00 

tfittedL. £110.00 

Upgrade of BBC Model A to B £90.00 

Please telephone for up to date informatton on Prestel, Teletext, 
speech synthesis, second processors, etc. 

TORCH Computers 

Z'80 Disc Pack for the BBC Microcomputer. £895.00 

This unit connects to the BBC Micro in the same way as a 
normal disc drive, but as well as offering a dual 2 x 400K disc 
drive for use under BBC BASIC or other languages it provides the 
option of using the wide range of CP/M software available for 
busine^ and data processing applications. The firmware supplied 
with the machine allows switching between BASIC and CPN, a 
powerful operating system developed from CP/M 2.2. 

In addition to the disc pack a second processor is supplied. This 
is a Z-80A with its own 46K RAM card, communicating with the 
6502A in the BBC computer through the Tube'. Typically the 
speed of execution of programs under the twin-processor system 
is increased by up to 50% compared with a conventional single- 
processor computer. 

A third processor, the 16 bit 68000, will shortly be available. 

TORCH CF240 £2,795.00 

(Ex. VAT) 

This an extension of the BBC microcomputer/Torch disc pack 
system, available in a single unit. The computer contains a BBC 
based peripheral processor connected to the main 2-80 computer, 
a dual 2 x 400K disc drive as described above, a high resolution 
(80 character) colour monitor and a complete British Telecom 
approved 1200 baud modem. It is the only microcomputer which 
has been granted permission for direct connection to the Public 
Switched Telephone Network both in the U.K. and the United 
States. 

The TORCH can communicate either directly with another 
TORCH or with virtually any other type of computer via Prestel. 
Using the Gateway facility of Prestel it is possible for the TORCH 
to access vast amounts of information stored by private 
organisations on public database systems. The Mailbox facility of 
Prestell also allows the use of electronic mail. 
TORCH CH240/10 As above but with a 10 MB hard disc drive. 
TORCH CH240/21 As above but with a 21 MB hard disc drive. 

Peripherals 

Seikosha GP lOOA primer £229,00 

Epson MX 80 F/T type 3 printer £389.00 

NEC PC 8023 printer £389.00 

Micfovitec t4" RGB Monitor £299.00 

Kaga 12" RGB Monitor £280.00 

Sanyo 14" RGB Monitor £260.00 

High resolution \T' black/green monitor £85.00 

Software 

We currently hold in stock programs from the following suppliers: 
Acornsoft Level 9 Software 

A & F Software Molmerx 

Bug Byte MP Software 

Computer Concepts Program Power 

Digital Fantasia Salamander Software 

Golem Software for All 

UK Software Superior Software 

Unfortunately we are unable to supply software by mail except as 
part of a larger order. 

Delivery by Interlink of any of the above items £10.00 

Unless otherwise stated all prices include VAT. 

SIR Computers Ltd. 

91 Whitchurch Road. Cardiff 
Telephone (0222) 21341 



142 YOUR COMPUTER. MARCH 1983 



electronics 



Spectrum 



MONEY BACK GUARANTEE 
CASSetTES DESPATCHED 
WITHIN 48 HOURS 



ABACUS CONTROLLER 



AVENGER 



»*-«qI 



Of alt the Spec H/W 
ftems ) have received 
this one moit 
lmpfe»ed me and its 
the only one t shell 
always use. 



'^^> -1?^ 



Developed to efiminate tedious swapping of plugs when 
LOADING or SAVING programs on cassette. 
2X SPECTRUM CONTROLLER: Single switch selection of 
SAVE, LOAD & AMP modes. Built in amplifier and loud- 
speaker boosts Spectrum sound output. Price £14,95 
2X81 CONTROLLER: Single switch selection of TALK, SAVE, 
CUE & LOAD modes. Built in microphone/speaker for fast and 
relfable program naming and cueing. Price £9.95 

All items in this ad%«rtisennent can bo viewed before buyirg at the Suffer Micro 
Shop, London, and Jay Dee Communications, Water Street, Port Talbot, 



AVENGER: This all action arcade-styte game written in 
MACHINE CODE for the ZX Spectrum is fantastic! You are 
flying over a mountainous planet terrain. Your mission is to 
attack, using lasers and bombs, launch pads, buildings and 
missile silos. Alien craft attack you with missiles; guided 
missiles launched from the ground hunt you out. But what ever 
you do don't hit the atomic power stations! I Continuous 
display of lime, score, shields and laser temperature. Five 
levels of play and high scores. 
Price £4,95 inc. Also available for the 2X-81 (16K) at £4.95 inc. 

Available at W.H. Smiths 

SPECTRUM GAMES PACK 1 

DESTROYER: Listen to the beeps of the sonar to locate and destroy 

- . ^^g submarines before they sink the merchant ships. 

I i^K,/^^ I CEBER G: Steer your icebreaker through thickening pack ice 



AH 

four on 
or>e cassette 
at the incredible 
p*m of £4.96 inc. 



to pick up survivors. 

BATTLE: Destroy missile sites while avoiding mines 
If .^^; and the computerised enemy tanks 
'rsr "^^Withat are out to get you. 

.< . ^ ANDROID Rescue the miners before 



FPIT RESUCE: 



t86 St Helens Ave, 

Swansea, W* Glam. 

Tel: (0792) 50282 



they are trapped in the 
flooding mines. /-^4=^'*^»v I 



■'%: 





■ IHHIIIUHHIIIIItlllHIHHimilttlHIIHIIIIIIIHIIHIIHHIIHIHIIItl l lHIIUIIHHUI I tM 

H&H 
SOFTWARE 

Alphabeta 

A complete word processing package for the BBC Computer. 
New revised version incorporating: 

# faster printing 
compatibility with a range of printers including Seikosha, 3 
Epson and daisywheels. Versions for other printers on S 
request, 
manual 

labels for the red keys 
automatic wrapround 
insert and delete (with gap closure) 
centring 
tabs 

right justification 
automatic word count 
merging 
double width characters 

# bulk movement of text 
and a host more features. 



i • 



# 

m 
m 
# 






REVIEWS 

Laserbug: "The program did work well and once you are used to S| 

it, writing letters etc, becomes very easy. I was inpressed with it gi 

in general and would buy it myself." 

Acorn User: "Remarkable value - a complete word processing ^ 

package for less than £30 ... a useful and relatively inexpensive 3 

program," 

ALPHABETA £28.50 including postage etc. 

Please send orders and cheques/ PO/Transcash (No. 614 131 5 

1707) to: 

I H&H, Dept A, 53 Holloway, Runcorn, Cheshire. | 

S Send S.A.E for 9 cutahgue of out oOm educ^tiona/ ami games prograrm for the BBC ^ 
3 and Dragon Compvtars. 3 

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UP TO 24 STANDARD OR 
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s.a.e. please for details to 30 Lake Street 
LEIGHTON BUZZARD Beds Tel 0525 376600 



YOUR COMPUTER, MARCH 1983 143 



EXPAND YOUR 
VIC 20 

with a matching aluminium plinth with 
appropriate holes and power supply cover 
(add your own electronic parts) 




Send cheque 

or P.O. with 

order delivery 2-3 weeks 

We are manufacturers of electronic sheet melalwork 
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iTHE GREATEST PROGRAMMING 
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• The attractive perspex stand can tw positioned where most comfortable, avoiding stiff 
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• The EASIRfAOER keeps your place for two-handed keyboard entries, i.e. when using a 
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• It witi even scan the olt-nori2ontai listings found m many magazines, 

« The EASIREADER can handle all normal magazines up to A4 size, single sheets, computer 
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ZX81 16K - GAMES ON TAPE 



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BANK ROBBER £4.50 

SEE HOW MUCH MONEY YOU CAN ACCUMULATE 
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cfc 



MAU ORDER ONLY 

NAME 

ADDRESS 



CODE. 



I enclose Cheque/P.O. for £ . . , 

Made payable to: 

LEON-NOEL 

24 Dudgeon Drive, Littlemore Oxford 

0X4 40 L 



ALL PmC€S fNCLUOE P&P. UK ONLY 



MEMORY DEVICES FROM: 

GCC ELECTRONICS 



Tel: 0223 835330 



Telex: 817672 



PONTOON £4.50 I 

CAN YOU GET YOUR COMPUTER TO OWE YOU I 

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HANGMAN £4.00 { 

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WILL HAVE 150 WORDS TO CHOOSE FROM 

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PUT YOUR ZX PRINTER TO WORK AND MAKE YOUR 
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PL£ASe TICK APPROPRIATE BOX(St 



EPROMS 


6500 FamBy 


MEMORIES 


2708 20Qp 


6502 


375p 


2114LP-2 90p 


2716-^SV 200p 


6520 


285p 


2114450 85p 


2732 38Sp 


6522 


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4116-150 SOp 


2532 365p 


6532 


520p 


4116-200 B8p 


2764 6.80p 


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4816-2-^5V 250p 
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6800 Family 


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6116150 350p 


6800 270p 


CPU 


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5516-250 635p 


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Orders from Government, Educational and Overseas buyers welcome. Special 
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Minimum order £15.00. 



GCC ELECTRONICS 

66 HIGH STREET, SAWSTOIM 

CAMBRIDGE DB2 4BG 

TEL: 0223 835330 TELEX: 817672 



144 YOUR COMPUTER, MARCH 1983 



Hm Good is VOUR Spectrum 

If you're interested in finding out what your Spectrum can really do then you must go 
beyond the limitations of BASIC. Now, mastering machine code can be a reality with 

CRYSTAL COMPUTING'S MACHINE CODE UTILITY PACKAGES 



ZEUS Z-80 ASSEMBLER 

ceopwtcr IIkq iCEt'S w th« perfect t 



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Optimura ratmory uMfc: >> oulaujniat )i\ own (ocufvoLMd text wtaadi in 
cocnplKtely Mptftic from BASIC, EEV'S tU^avi you to es'.cr non Otin SOOO 
m4i%iji^ liMi Of text (ttUcvh 4ucinbki jv-,o m^^c tkAa 5IC <»f n>i>%iar oodc1> 
T^ ultimalf etfiorr K vti«m tt^^frckCAor »t>i< fuU xtfcfl odiier tlovt 
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liMi 91 Uf 10 U «lMficUfi m ttnfth ar* .-^^ntd for. *lMf «Wl BBaMiny Mi 
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•ddJdeo 10 MocpdM AU. lundiid z 10 miuwdow, 2SUS abo nvpOfU d^ 
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Dtrtct *ocm to memofr: To funhcr ctk&tncc Z£CS, u i»vttci;Me ooeicot i)icca 



« iM3od«d AS STANDARDl Opcrttiat «ii& tb« hac fror-f< 

■Miyidai lopoi a kcx. tfecteMl Of ct«»ct«f foTB. i^ nowor il0«t yvvift tiialitf 

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labirfue. co^y a^ bex/^Avcwtil coo^'wi- 

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Z£US is ifi tto ptui aMNfe oMce. [f rcprefenti t po^ivtful MaLacbiMoo^ ofwratoit 
tyiicia KltRfei If ^ettbted to beoMM ii much 4 pui of the Spectran ai t^ Stftcl*k 
ROM 

MONITOR AND DISASSEMBLER 

Thtt «uy to u»c utility enittet fu.: ntctr. f^ditiQC aai <«bM|ta| «f b eaad t c i aa l 
rout^pet U rcsi,irn oae-:^ud& KfcVWORD' Lopwi aa fci SJociM tASIC. >>iMerieal 
pwaBCtcn «ay ^ eoterod ia cuber 4cCimaJ «f bo, aai a tacBty b p o* i d »l to 
HfiadraiMl total «r «MfelM<coddt aaay be 

-_.„ , -ifti ihf rtjtoe «Udi i ap t>y i die coattwi ^f i 

aptcUM ana «l ntoiory ia bocK bej^aJecunil tttd cbfine4«r form. Tbe vem m«y 
IM HM tbe i^uiteoiblec «o eonvert lite auabcn back into Z^ BacBOcita. Two 
•OCaMe deboisicis aldi Af e tU cotDmadt blt£AKP01NT and REOISTEKS, v^tcti 



caa provkd* i futt dnf>Uy of ite valMi Md w al CP.U. remtcn, roc***^ tbe 
alWMtt t«t *fvd Hm' . IT ^y poiM is ibf PMfpan. AIM iadtided are 
laam wt mp or cf^ftcim, to priai. laMiit, com aad ««rtfy blodU of ■e n ofy. 
aad a unique 'jump ; cUij^e' caloilaior to wMMi me eoenct olfiet byic la JR lype 
lAMnnetiotu. The rooniior furtbirr p«««idc4 a *er«aiik HND cokwawAd wtekh «il] 



k 1 wedfkd block of lOfBory aad dttpky al oocsfenecf of ftSy 4«U it iri» 
ukc4 10 fiod. 

Tbe«e fc4tuf ei, t<^ rf »1 r tua facttUd, plai hM pftAter dnvn mtke tKi« umpty tfcc 
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TV SPECTRt Kt MOSfTQR AND 0ISA$S8aaL£R bat been dei^toed ai tKe 
perfkt cowiirttiDet to tbt 2SUS S&49 ASSEMBLSR. liaviat boti eo-f«i«ieaf in 
MtaMfT |h«» yen dit •tMBMt ■■AhmJi »««•' Nov yov caa explore chc 
" c of yoot conpilir Mtf OfM i^ i *lMlf mv world of pfociamttlnf ! 



ZX-Sl SUPERFAST LOAD AND SAVE 

Ow Mottitor aAd Ottaj^terebin *.\ a%itlAbk ri>f iHe !6K 7X Ht alio iMludci 
eoa«u*di w LOAD and SAVE »ay bl»;k of raesMey imckdAf SASIC pfOfrtmi) 
at a^ 10 F04JR TIMES aoTMal »pe«d! 



Each utility comes with detailed user manual for only . . . £8.95 
. alternatively, try our own range of exciting and original ZX games: 



H**t you ib« ikitl aad ren«Mi 10 c««Arol « teviwhae if«cc frtiilMfr fro* 

Him |M Cfca btMiacn bead 10 End* iaooeuf«tT tbrp<|boat tbe let^ tad breadtb 
otaaaatfwalaaWt 

wwv OM wf baoMii^ a 

MERCHANT OF VENUS 

it4(ff a (onpkai ccooook Meoaho 11 combiaed witJi 4 itijmb fjaplik Kiwi^attoa fjo 
wodoct aai cacinly eeur oocKfpt la laal tine advcatvre*. 
By mtCgi^ tbif cunent marlft aad wterf^aad dcaiot ia Cyborft. RobodfOoe* 
Md mvdi mmt, ym ouatt piia ymt tailnn nnarfy. 



B«t iUtiaate^ ywtr luceait deprad* oo youe abtlfty at t pt(oi;.froea bfi^ff u you 
tbmtt tlt¥«aid . . . dumf fi^iti as you coatrol your ibioH n^t o«ct atnnaiimr, 
ekie»iMOCC»». . to Uaifeit wtwf* ^^wdeicemi a ditpkyed la ixftdJMi pif bfc 
dciatL 

Aed«p(fittt(W<ofikdlaadKnicsyfortbct6KZXti Um. 

ZX II IKOAWS PACK: WHkoec do«b« ib« flasi 4«ito eoOtctiaa for tbe IK 
ZX f I:— 4 im wattm, tm mim pMpbkt pmo. al wkk d ^ i c f w a KoHDi: 
lavadoK Aitavoid. Bombct aad Siiper Slakeoi, pbu a rhilmt^ adt^iurt. 
Duoffoo Qoeit. 
Att lOOt^ aia<itiMs<ode,Of«atva)oeai £4.95. 



COSMIC GUERRILLA 



?%• daaik arcane pan ti now «t«UaWe f«r tW SC S po ct n im . Wfiiica !■ tOO% 
ltTiu»upeT-i»ooib«seto«r|fafMciaadioMd.YoiiaHMdcfi ' 
l««r taict bttia Hseifui inccuMU «taci by »ott winalai af(«k POr IMt t 



iitadhmc code* wnb f 



« »upeT-i»oolb cotMr I 
Hseifui inccMMU «taci by « 
OC Spcctnnf ».....'..... MSf 

THE DUNGEON MASTER 

Dunteont a»d Dr«foa« f«« . . . I«i £be UK SpcctnMi be yotw D.M. wkb dbc fvu 
> Ititr iaio tbe true ifttit of O A D. Ill mit/m duAKon 
I to er«a«e your ov* oomta tMMitoi oakUy ead 
I uflicte diPHMXi — bank ycm way ibro«i^ a ae« 
aia faaiaiiy. As iafiAdy of pouibiltuet for o«y . .... ft 95 



Send Sae /or owr latest catalogue. Please add £0J0 p&p and make cheques POs etc, payable to: 

CRYSTAL COMPUTING, 2 ASHTON WAY, EAST HERRINGTON, 

SUNDERLAND, SR3 3RX 

TRADE ENQUIRIES WELCOME 



REGISTERED REFERRAL CENTRE 



FOR THE BBC PROJECT 



beebug;s^ 
bbc micro 

INDEPENDENT NATIONAL USER 
GROUP FOR THE BBC MICRO 



MEMBERSHIP NOW EXCEEDS 10,000 
10^000 members can't be wrong 3EEBUG provides the best support for the BBC 
Micro. BEEBUG Maga^Tfie - now 36 pages - devoted e^tclvtsivetY to the BBC 
Micro. 

Pfo^raois — Hints & Tips — Major Articles — News - Reviews — Comnner)tarY. 
PLUS membefs discount scheme with Natiortal Retailers. 
PLUS members Software Library. 

10 Magazines a v^r, Brst issue Aprit 13S2. Reprints of all tssuos avaitabto to 
members. 

October Issue. Program Features : Alien Attach, Calendar Generator, Union Jack, 
arid Memory Display Utitity. Plus articles on Debugging, Improving Key Detection. 
Acorn Press Release on O.S. 1.2 and issue 11 Base. The Tube arKi Secornl 
Processor Opiioi^, a New Saries for less Ej(perienced Users and Softwafe 
Reviews. 

November Jsstie. Program features: Racer (excellent 16K ractr*g car game). Mini 
Text Editor IMk2)^ Transparent loader. Music with nwmory, Harmonograph 
Emulator. New character Ser for modes 2 & &; and cassette bk>ck*z«fO'bug retrieve. 
Plus articles or soured and crwelope design - indudes indtsptnsable envelope 
editor program; Debugging Part 3, Seiial printer pert (RS423} and RGB upgrade. 
Plus a large number of Hints & Tips, and a guide to our pa« issow and theii 
contents. 

BEEBUGSOFT: BEEBUG SOFTWARE tlBRARY offers members a growing 
range of software from t3.S0 per cassette. 9 groat cassettes are currently 
pack available: - 6 oxcollent games such as Starfire; Utilities pack 1 
contains 3 usefut programs: character definer, disassembler and mini text 
editor. 

These prognams are available to members onty. For prices and fyrther 
details join BEEBUG. 



Send £1.00 & SAE for Sample. 
Membership: UK 4.90 for six months 

8,90 for one year 
Overseas one year only: 
Europe £15.00 Middle East £18.00 
Americas & Africa £20,000 
Other Countries £22.00 



Makn cheque to BEEBUG 

and a«nd to: 
BEEBUG Dept4 

374 Wandsworth Rd. 

London SW3 4rE 
Editorial Material to PO Box 50, 
St Albans, Herts, AL1 1AR 




SINCLAIR 
COMPUTERS 

UK pfices are slKiwn fir»t. The bracketed prices are expo^ pnccs which include insured 

air-mail postage to all the countries of Europe includir^g NonA^ay, Ssveden, Finland and 

Denmark, for overseas customers outside Europe an extra €S postage per item b 

charged. 

2x81 £43.43 (52). ik printar €52.13 {61}. ix sprectrum 16K £152 (160). 2X spectrum 4aK 

C202 (C210). ix microdrive n/a (n/aL 5 printer roils £10 43 (16). 

Rom pack5: 16K £26.04 jf28J, 32K £39 W). SeK £49 t51). 

DRAGON 32 £173 
COMMODORE COMPUTERS 

Commodore &4 £299. Vic 20 Ct30 Kit to alkw the use of an ordinary mono cassette 
recorder with the Vic 20 and the Commodore 64 £6. Commodore cassette recorder for 
these computers £3G.S0. Super expander high resokjtion cartridge £27.95, We stock 
most accessories. 
BBC MICROCOMPUTERS 

A Mode! £260 8 W<xJd r347 

GENIE COMPUTERS 

New cok>ur Geni** £ 1 73 so, 16K ram card £44. light pen £15. Accessories for Genie 1 and 
genie 2: - EG3014 32K ft89 Disc drives stngle £199, dual £369. OouWe density 
convertor £72. High resolution gr,*p*MCS £62- Prmter interface £36, 

UK101 AND SUPERBOARD 

3^x48 drsplay expansion kits UK101 £9, Series 1 Superboard £14. 32K nr^emory 
expansion board £60. Cegmon £22.50. Word processor prog £10. Centronics interface kit 
£10- Cased disc drives with DOS single £275, double £415. Stand ak>ne floppy disc 
COnlroiJer £85. 




PRINTERS 

Buy any of the below and get a free interface krt and word processor program for UK 101 
or Superboard. Epson MX80FT3 £324. Epson MX100/3 £425. Se*osha GP100A £189. 
OKI Microfrr>e 80 £199. OKI Micfolinea2A £333 OKI Microdne 83A £446. OKI MicrOline 
S4 £666 OKI Mfcrolme 92 £429. OKI Microline 93 £586. 

5V POWER KITS 

Fu Uv stabilized 5V computer and TTL power kits. 1.6A £7.83, 3A t12.17, 6A €20 J7. 

SHARP COMPUTERS 

We can Supply Epson MXdO And MX 100 printers to run direct from the MZ80K (i/o box 
not reeded) for £39 plus pointer ^r\ce We also specialize m tnierfacing printers to the 
MZ80K, M280A and MZ808 both wfih and v\ithout the i^o box 

SWANLEY ELECTRONICS 

Dept YC, 32 Goldsel Rd , Swanley. Kent BR8 8EZ. 

Tel Swanley (0322) 64851 

Postage ff on StncJstf products (UKK C3.iOon other computers, €4.50 on prmtcrs And 
50p on othfr orders. Phast add VA 1 to atf prices. Offtci^i credit And overseas orders 
wetcome. 



YOUR COMPUTER, MARCH 1 983 146 



ZX81 SPECTRUM DRAGON TANDY BBC 



16K 



16/48 



ADVENTURE 

I * Over 200 places to explore in this machine code game using 
advanced data compression techniques, 

* No random elements — you will need skill, cunning and a 
sense of humour as you explore caves, forest and castles. 

* Evade ruthless pursuers and overcome a host of obstacles. 
I ♦ Multiple word commands and single letter abbreviations. 



LEVEL 2 



A/B 



AWARI 



* The ancient African game of logic. It takes 2 minutes to learn | 
the rules but far longer to master the tactics. 

* Select the *Goat-herd* level of play and it's an addictive game I 
for children (8 + ) that exercises their minds — not their laser) 
fingers. 

* Select the * Witch-doctor' level and it's a threat to your| 
sanity. We haven't beaten it and we wrote it! 



£1000 IN PRIZES 



FANTASTIC VOYAGE 
(ZX81 16K ONLY) 

This real-time graphics simulation set inside the human body 
was written by a lecturer in anatomy. You arc injected into the 
blood stream in your miniature submarine. Navigate the 
arteries, veins and heart to the brain, where a blood clot must 
be destroyed. Features a real vasular map. You will be 
attacked by lymphocytes which must be destroyed using 
arcade game type graphics. Everything you do uses up 
precious energy. Three display formats — a lateral and frontal 
body scan plus blood vessel name, a close-up scan and a laser- 
sight for fighting lymphoc>ies. 



** Buy both Awari and Adventure and enter the Toilkade 
Challenge* competition. Details with cassette or send SAE. 

FOILKADE LTD 

DEPT. PR9 

66 LITTLEDEAN, 

YATE 

BRISTOL BS17 4UQ 

ALL GAMES £5.95 EACH, 2 FOR £9.95, 3 FOR £13.95 
(ANY MIX) INCLUSIVE. 



HUGE SELECTION-^OVER 400 IN STOCK! 



HIRE 



ZX81/SPECTRUM 
PROGRAM TAPES 



Get the most from your ZX81 or Spectrum at minimum cost by hiring 
program cassettes for lust £1 each per fortnight (plus 40p p/p). 
Our stock of over 400 tapes (up to 20 maker's original copies of the 
more popular ones) covers most of the best cassettes advertised In 
this magazine— and more: thrilling m/c arcade and adventure 
games, tests of skill, realistic simulations and a wide range of utilities 
for business, multi-Indexing, banking, toolkit and graphic aids. 

You can switch from ZX81 to Spectrum membership at any time by 
paying the balance, and hire up to three tapes at a time. Our regular 
Illustrated magazine "Computerchat" Is posted free to all members, 
with Its product and software reviews plus our unique "Top Twenty" 
ZX tapes chart based on members' scores, and some special offers. 

"An exceptionally professional and thriving 

organisation with, even, a most readable 

newsletter"— review in Eric Deeson's "Guide to 

ZX Spectrum Resources." 



The Sinclair Owners' 
SOFTWARE LIBRARY oeptYC, 

Heather Cottage, Warren Road. 
Uss, Hants GU33 7DD. 

Yes, please^ I *d like toioln for the next 12 months. Please send on 
money-back approval my magazine, descriptive library catalogue and 
order forms, on the understanding that If I'm not delighted with your 
service within 28 days you will refund my money In full. 




NAME. 



ADDRESS. 



.TeL 



I enclose cheque /Postal Orders for: 

n £6.50 for ZX81 membership (overseas £2 extra In each case) 
C £9.50 for Spectrum membership 



in stock now 
at Twickenham's 
official BBC/Acori 
dealer & service 

centre 



;j^n 






O(D0 



Model 
A&B 




plus alt the extras: 

Printers + Monitors + Disk Drives 

+ Cassette Drives + Software + Books 

PLUS VIC'20 Cassette decks, games 
cartridgeSf^ tapes in stock! 

Always available -a wide range of micros, 
software, printers, peripherals and books 
- send SAE for latest lists 

TWICKENHAM 

COMPUTER CENTRE LTD 

n Nnth Hd Tvkkiikani MMtfx TWI 4SW (01-892 7896/01-891 18121 




146 YOUR COMPUTER. MARCH 1983 



Buy from us with confidence 
Full money-back guarantee on all our products 

"Thank you once again for your prompt service; yours 
must be the most user-friendfy company in the business f' 
as. Yorks 

'7 must congratulate you not onfy on the quality of your 
goods but also on your excellent service. " G. W, So/ihull 

Quality software 
ZX 81 Spectrum BBC Vic-20 

GAMES CASSETTES 

2X11 (1*K» SUPER INVADERS ... C4M 

0ft-t4*Mn ItaguA uW«t, dfvrnttMi iitlnictions. <km* «> rnachki* code - "exMitni 
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2xai nexj lynch mob w.ss 

EkOis«i9 word 9im0. 3-$ ptev«rt. Exc««*rit to« Ch4 r«m^. Gt*it hjri, tdvCVIiOntl lool 
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Spm&ttutn (1«C) LYNCHMOfi. . . . . . . .Ce.SO 

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APPLICATIONS SOFTWARE «.«»«,. 

ZXtt IlKl GflAPHlCS STARUH PACK, . t*.U> 

ZXn (WKI MULT10RAPHICS , . C6.90 

A M%tf Ux^rxSy p4cic»9«i 0^ p'Mfdvrts QfvinQ vcwi Kit e«ntrot of itfie 2X8'> Qf«pl»ct 
fur<tioo» »» compOMi dMigns, d(^wir>g», •dn^titi tte. liico<pO'*tr» »dv«f)c«4 »k«tchp«^, 
d t<x«» of Itxx (vtdutffio po^ cut), •nimetlon, prinitf ovipuT, SAVE ^iftptav* ttc. 
BvtinHsmm um it Co wlv«ftiM at point'Of ■»!•. 20 p^ Mamiir. 

Sp#etrymf«KJ SPECmOGnAPHICS - £6.90 

A/ioih«f &op»rb ii««r<fr;«rsi^}Y Qfiphtc* program - hMws And to-ros sluichpads, muHtatM 
»i,t, etc. esc. 

2XW 1KSTATIST1CS €4.00 

MM n y SQf va4i*Ac«. co<T«t«o^n. fe9re«*ioci, 1 «nd F t«sts. d pp M«no«l Wc^idM iMtng*, 

Sptctrum t48K» STATISTICS tprJct iTKludM m^t«nanc«J CdJO 

M#aA. SD. var-ar^c«, cort«l»$ton. <'*o<'M«*oa. t t«m Hi>r«« 9f>«p^«e <Ji«p%y«. dfl* 
rfMrwptt'.aton proccdufe*. 

E^HEMIRIS rXil »1|K>. . , teJO SpoarumllSK, 4aK» a 90 

lAt«p*«lf<t in h««v«olY tKKM*? Input dM«, txvM ttfid yo*jr po«t>on, Cph«<n«m coffifimt* 
MitvOt. Aiimuth. phiM etc «tc. M Km, rnoof^ «i^ ptenttt. 

16K RAM pack Mamot«ch Mamop&k 16 £28.50 

AJNrKkfVV* pnoft f>fU 0*ss rtrvrrt cf-pcit m»d m UK. 

iufoptm aatomm *dd 30p pvf *><m; ?0p v/o/f(fM4ff fAv M»if 

AvtJ^tit by ffW Of^ftf &f from frfd^ng cc^irifK/ft/ iKfrs. Trod* tftq^nn^s wtit^ffn». 

Dept. YC, 36 Fernwood, Marpio Bridge, 
STOCKPORT. Cheshire SK6 5BE, ENGLAND. 








Keyboard with 
Electronics 
for ZX81 







^r% 



A hJ-stze, full travel 43 key keyboard that's ^mple to add to ytiur ZXBt and 
requires no soldering in the 2X81. 

Complete with the electronics to make "Shift Lock" "Function" and "Graphics 2" 
single key selections making entry far easier. 

Rowered from ZXSVs own standard power stJpply-WTth spedal adaptor supplied. 

Tw^lour print tor key caps. 

Amazing low price only £19.95 incl. VAT and carriage. Order As LW72P 

Ml details in the June 1982 issue of "Heclronics-Tlie Maplin Magazine" on sale 
at all good newsagents price 60p. In case of difficulty send 60p to address betow. 
Of £2.40 for annual subscription 14 issues). 



imifiiipiLJiin) 



Electronic Supplies Ltd 
P.O. Box 3, Rayleigh, Essex SS68LR. Tel (0702) 552911 

Retail shops 3t 

159 King St., Hammersmith, London W6. Tel 01-748 0926 
284 London Road. Westctiff-on-Sea. Essex. Tet (07021 554000 
Lynton Square, Pterry Barr, Btrmingham. Tel: (021) 356 7292 
(Shops closed Mondays). All mait to Rayleigh address. 



•7\/OT 
L/\Ol 




from 
J.K. GREYE SOFTWARE LTD 

''Without question the finest machine code games available 
today::, J.N. ROWLAND Product Manager for W.H. SMITH. 



QAMESTAPE 1 for 1 K 

10 GarTi«s incl. ASTEROIDS, 



o«itY£3.»6 

BOMBER, 



UFO. CODE 
guillotine: KALEIDESC0P6, etc 
PROBABLY THE BEST VALUC tk TAPE AVAIiABLE 



We've done in Ik, games which sorr»e of our competitors 
reQutreTSktodof 





GAMESTAPE 2 for 1SK oo»y C3.96 

•STARFKjKTER Superb machifke code Space Battle. Set 

against a backQfOur>d of twinkling stars, with stunning 

t*xf>tos»Gn!i — if you can hit the enerny! 

PYRAMID Can you move the Pyramid? Make a mistake arvd 

it will coliapso! A Thinkers game. 

ARTTST The ultimate Graphic Oes^nefs aid. % Directions, 10 

Memories, SAVE, COPY. RUBOUT. CLS. etc. 



QAMESTAPE 3 for teK 

'CATACOMBS A MuUi-Levd Graphics Adventure! 



0niy£4.i5 

Each 



level can contain up to 9 Rooms, 8 Passages. 7 Monstecs, 
Food, GokJ, Traps. Phanton-is, an Exit (to the r^Kt level}, 
and there's an infinUe mjmbe^ of levels. 
NOTE. . , . This is NOT one of the necessarily limited text 
Adventures as sold elsewhere. 

*i4n e^cefhnt addictive gome whtch vwtf k^p yOu mrmsed 
forhOitrs!'. . . . COMPUTER a VIDEO GAMES. 



;i 



i.v^ 



T7^ 







GAMESTAPE 4 f or 16K _ 
3D M0P4STER MAZE 



, only £4.96 

At( Others, 



The GdTM? to Top 
UntMfliovijtik! Gr^jphics? Can you find your way through the 
Mdio' The EXIT js there somewhere, but iNn so is a T, REX. 
and its after YOUf All in 3D (t)ie T.REX Mill actually fun 
towards you m fuH perspective!*, you've never seen anything 
like this befOfe< 

'^3D MONSTER MAZE is the best ca'"* f '^av* seen for the 
ZXSn . . . COMPUTER b VIDEO GAMES 
*// / h»d to choose /ust one progremme to impress en eudieoce with the capabif tries of 
the ZXSt, then JK. Greye's 3D MONSTER MAZE woufd te the one without doubt" 
. . 2X COM PUTING . '^Brmani brmmi bfmntrr . . . POPl/LAR COMPUTING WEEKl Y 



GAMESTAPE 6 for ISK . 



.only £4.96 



*3D DEFENDER The Ultimate Space Game. Super fast 

Mactiine Code 3D version of the Arcade favourite. You have 

to savD your hofnc pUinet from tfw morauding Alien Spacecraft 

This is all in 3D. your viowscfcen shovb^ you the view out 

of your fighters cockpit window. The backdrop moves when 

you turn, or fly up or down (8 flight directions), jost as if you 

were realty flying tt! 6ut then YOU ARE! The Enemy Saucers 

wilt actually zoom towat'ds you in 3D, ar^d shoot yoii rf you let IhemlYour display 

ir>c!ud6S Score. Shidd Strength. Altitude. ProxinriCy, Forward Radar and youi v^ewscreen, 

which showrs your rotatirvg home planet, backdrop of Stars, Meteors, Exptosk>ns. 

Plasma 8l^ts, your Photon Beams, up to 4 Enemy Saucers and of course its aJl m 

full 3D I 

"Another 3D winner". .^. , . StNCLAtR USER 





GAMESTAPE 6 for tK. 



.Ofilvt1.96 



* BREAKOUT Super Fast Fuli Screen Display Game. Your 
aH tin>e favourite vwth an added twist. See how much Money 
you can win and watch the pounds convert to Dollars, AW 
in Machif^ Code for Fast Action with 3 Speeds, 2 Bat Siies 
ar>d three angles of rebound I The best BREAKOUT drour»d 
arvJ at this price yOu can't go wr ongi 

'The best of its kind" WHICH MICRO & SOFTV/ARE REVIEW y 



GAMES MARKED * INCL. MACHINE CODE. 

Prices indude VAT and U.K. P. & P. 
(Add appropriate Postage on Foreign Orders L Cheques/P.0,5 to 

J.K. GREYE SOFTNA/ARE LTD 

Dept yC 1 6, Brendan Close, Oldland Common, Bristol BS1 5 6QE 

CREDIT CARD SALES: FOR INSTANT DESPATCH BY PHONE ONLY 
TEL: 01.930-9232 (9 am • 7 pm) 



If you prefer to see before buying, our range of GAMESTAPES 
are stocked by the foJtowing stores. 

BUFFER MICROSHOP 374A Streatham High Rd., London SWIS: 

GAMER 24 Gloucester Rd., Brighton; 

GEORGES „. 89 Park St., Brtstoi. Avon; 

MICROSTYLE 29 Belvedere, UnsdOwn Rd.,8ath, Avon; 

MICROWARE 131 MeitonRd.. Leicester 



SCREEN SCENE 

W.H.SMITH 

ZEDXTRA 



— 144 St. Georges Rd.. CheltenJwm. Glos; 

— Over 200 Computer Sra^^chcs; 

— 5 School Lane, Kir^son, Bournemouth, Dorset: 



TRADED EXPORT ENQUIRIES WELCOME 



YOUR COMPUTER, MARCH 1 98 3 147 



midlmKl 

irnimter 




BIMCUYHAU, 
BIRMINCHAM 
28-30 APRIl 

«^J9^ Thurs & Fri 1 0am - 6pm 
twO^ Saturday 1 0am -5pm 




Personal computers 
Home computing 
Small business systems 



Presented by OOMMflBl 

This event is the first of Its kind in the Midlands, and gives you 

the opportunity to see and compare the enormous range of 

personal and home computers, small business systems, 

microcomputers, software packages, cassettes and scores of the 

very latest computer games - try them for yourself - decide how 

much, or how little it takes to build up your own personal 

computer system. 

HOW TO GET THERE 

BY RAIL Concessionary raff fares are available direct to New Street Station. 
Further details are available from, British Rail Travel Centre, New Street Station, 
Birmingham 82 2QA Tel; 021 643 271 K 

BY BUS every few minutes from New Street, Corporation Street, Colmore Row 
and Bull Ring. 

BY CAR Bingley Hall is situated Close to the city centre and is within easy access 
to the Ml, MS and M6. Bingley Hall will be road signed by the A A. 
Admission prices - Adults £2.00 Children under 16 and CAR'S £K00. Party Booking: 
For groups o1 over 20 people - adults £1.50 children 75p, (plus a free ticket per 20 sold 
for the organiser or teacher). 



Please send adult child tickets Enclosed remittance £ 

NAME 

ADDRESS 

. TELEPHONE NO 



Send to Midland 
Computer Fair Ticket 
OfficeJ.RC, Exhibitions, 
Surrey House, 
Throwley Way 
Sutton, Surrey 
Tel: 01-643 8040 



'jti flhiilliiiiillllltlllt 



III 




M8 YOUR COMPUTER, MARCH 1983 



^mmm 







Just getting started in computing? Or perhaps you're 
already pretty knowledgeable and would like to extend 
your programming skills. Either way Your Computer 
back issues can help to fill your need for reliable and, 
above all, relevant information about home computing. 

Every issue contains reviews of new computers, 
software evaluations, and surveys of add-on equipment 
together with informative articles which tell you how to 
get to grips with graphics, sound and machine code 
programming. 




Facilities provided on the Sinclair ZX81 and 
Spectrum, Vic 20, Acorn Atom and BBC micro have 
been examined in article after article, providing a 
comprehensive introduction to all the most popular 
home computers. Just run your eye down the Contents 
of our back issues and you'll see what we mean. 

To order back issues complete the coupon at the foot 
of this page and send it with your remittance to the 
address shown on the coupon. 

January 1982 

Reviews: BBC micro; Word processing on Atom; Morphy v. 
Champion (chess computers). Game — Treasure House. 
Education — ZX81 programs for school use. Vic-20 Software. 
2X81 Graphics. A* D conversion. Interview — Kenneth Baker. 



February 1982 

Survey: 
Vic 20 
Atom Pi 
Borlam 



ny 1982 

r.j^Uk>i^^^ W^ C^^|iC$ ZXR^^m^f^^^^ 



igS. 



^^ 



To obtain any of these back issues please complete and return the 

coupon printed below. Prices per copy including post and packing are: 

United Kingdom: £1.50. Europe: £2.00. Rest of world: £2.50 (by Air Mail) 



April 1982 

Survey: 2X Ports. Sorting on ZX-Sl . BBC Graphics, How to write 
an Adventure Game, Atom Hne JabeHmg. Game — Nim (or ZX81 
and Apple 11. Interview — John Baxter. 

May 1982 

Survey: 2X Software. How to write a chess program. Garnes — Vic 
20 Tank Battte; Magtc Squares. How to show off your 2X81, 
Joysticks for the ZX81, BBC Graphics. How to write a word 
processing package, Inlervtew — Richard Turner, 

June 1982 

Reviews: Sinclair Spectrum; Vic 20 Software: 2X-8I Keyboards. 
Games Vic 20 Mars; Othello on Flexidisc. Atom Utilities, 2X81 
machine code monitor. How to build a portable computer 
Interview — Ron BisselL 

July 1982 

Survey: Atom Software. Spectrum Graphics. ZX-81 Colour Board. 
Games ~ Dog Race: Genie Guessing Game; Simon ChaKenge. 
BBC Sound, 2X-81 Disassembler. Programs for 2X-S0. Interview 

— Richard Altwasser 

August 1982 

Review: Dragon 32. Survey: Vic memory expansion. Spectrum 
Sound Games — Demon's Domain; Vie Duck Shoot. 2X-81 
machme code (Part IJ, Atom file handling. Ecological modeflmg, 
BBC techniques. Interview — Tony Baden. 

September 1982 

Review: NewBrain. Spectrum Software. Sound on ZX-81. Games 

- Vic Dambuster; B-52 Bomb Run. V)C-20 Assembler. Spectrum 
Disassembler. ZX-81 Indexer. ZX-81 machine code (Part 2). 
Midwich MC control computer. Interview — Hermann Hauser. 

October 1982 

Reviews: Sanyo PHC range; MPF-II; Commodore 64; Colour 
Genie. Survey: BBC Software. Atom Forth Pascal for Basic users. 
ZX word processing. Games — ZX-8i Pinball; Vic Catacombs. 
Atom text BBC control Key. Spectrum Assembler. 2X81 machine 
code (Part 3). Interview — Douglas Adams 




Issue (month) 


Year 


Quantity required 






























' 





















To: General Sales Dept., Room 108. IPC Business Press Ltd. 
Quadrant House, The Quadrant, Sutton, Surrey SM2 5AS. 

Please send me the back issues detailed left - for which I 

enclose cheque/PC for £ payable to 

IPC Business Press. 



Name . 

Address 



YOUR COMPUTER. MARCH 1983 149 



A 



A 




The assault on your 
senses has begun > 
with d great . ^ 
choice of games \ 
that have been u 
created to give ' 
you a real 
challenge! 








-«^.v 




/ 





^^^^^o"\x* 



.<=>^>'' 













\l*?^ 

r 



i/y 



..< \«* -■*• 



TT 



A 



j'A'^t, 



.o".",©-',© 




Any of these games for just 

£550 

^^% EACH 



including first class post, 
packing, VAT and an 
UNCONDITIONAL 
LIFETIME GUARANTEE 



When you buy Imagine Software you buy it for life. If an 

Imagine Software product EVER fails to load first time 

simply return it to Imagine for an instant free replacement. 

All ord#rs despatched by first class post within 

24 hours of receipt. 

Why not put a fir^t class stamp on 

your envelope and you will receive your 

order within 3 days of posting. 

Available from all good sofhware outlets. 

deolership enquiries contact: Mark Butler 



Imagine Software, Masons Buildings, Exchange Street East, Liverpo< 



coV 










Post coupon now to Imagine Software, Masons Buildings, 
■ Exchange Street Eost, Liverpool, Merseyside L2 3PN, 
* Please rush me copies of (tick box) 
I ED Arcadia □ Schizoids □ Arcodia □ Wacky Waiters 

n Ah Diddums G Catcha Snotcha 

(for any ZX Specfrum) (tor ony Connmodore VIC-20) 

I Please debit my Access/Borcloycord (delete os necessory) 

Cord 
H Number 



I I enclose Cheque/PO for £ . 
m Nome 



I 



Address. 



YC3| 



Merseyside 12 3PN. 




SUPERBXSrCREDITCARD SALES UNE: f^S^ 

051 236 684fe i-«,irs) "^^ 




Installed in 3 easy steps . . . 

1 . Peel off the touch sensitive key pad. 

2. Plug in Klik-Keyboard (no soldering) and place in 
position. 

3. Apply self adhesive two-colour legends to the 
keys. 

This full 40 key keyboard has a positive click feel as 
the keys are depressed but as it replaces the original 
touch pad it becomes a permanent part of the ZX8 1 
without bulky boxes or trailing wires. 

Other useful peripherals available from Kempston:- 

SPECTRUM 

NEW Competition-Pro Joystick £25,00 

NEW Centronics Printer Interface ............. around £35.00 

24 Line Programmable User Port £18.95 

Full range of Spearum software - details on request, 

HEmp^rron 

■^" MICRO ■ ELECTRONICS 
1 80a Bedford Road, Kempston, Bedford, MK42 8BL 



/ 



I wish to order: 



\ 



Quantity 



Item 



Post & packing 1 item £ 1 .00. 2 or nrK>re items £2.50. 

Total (VAT inclusive) 

Cheques/Postal orders should be nnade payable to 
Kempston (Mtcro) Electronics. 

Nanf>e 



Price 



Address, 



Post to Kempston (Micro) Electronics, Dept YC J 
180a Bedford Road, Kempston, Bedford MK42 8BL 



A 



THE PROFESSIONAL APPROACH TO 

SPECTRUM 

SOFTWARE 



We are a well established software 

company expanding into the field of 

Personal Computing. 

ENHANCE YOUR BASIC 

Now available BASIC toolkit includes: 

• Add logical arithmetic functions 

(AND, NOT, OR, XOR) 

• List all BASIC variables and arrays 

• Speed up your games with our fast 

screen output. 

• Renumber your program 

(including GOTO and GOSUB) 

• All routines in machine code 

• Easily called from BASIC 

• Fully documented 

• Runs on 16K and 48K SPECTRUM 

£9.95 inc VAT ( + £1p. &p.) 

To order or to obtain details of our other products contact: 



Malva Ltd. 

REALTIME SOFTWARE SPECIALISTS 



70 ASHCHURCH DR. 
WOLUTON 
NOniNSHIM 
R6B 2RI 



ZX81 CONTROL & 
MONITOR SYSTEM 

24 CHANNEL COMMAND CENTRE 

An exciting new concept in computer control with 24 independent 

channels operated by simple PEEK & POKE commands from the 

ZX81. Allows extensive control of all kinds of appliances and 

monitors their response. Superbly designed and engineered with 

extensive filtering circuiting protecting your ZX81. 

COMMAND MODULES 

A varity of control or monitor modules may be added to the 

command centre with its own indicator LEDs recording the current 

channel states. Comprehensive programs are easily constructed 

and checked because you can see the state and response of each 

channeL 

1001 APPLICATIONS: 

DOMESTIC: Control and Monitoring of appliances, heating, 

lighting models + security systems. 
COMMERCIAL: Atuomatic test equipment, office equipment, 

electric surveillence FIRE/DOOR/ INTRUDER 

monitoring iaboritory applications. 
INDUSTRIAL: Process control, level monitoring, detection and 

robotic/workshop applications. 
Complete with manual and excellent security program giving 
operation to BS 4737. 

SIMPLE TO INSTALL & USE, JUST PLUGS INTO ZX81 PORT; 
DOES NOT AFFECT RAMPACK or PRINTER. 



QTY DESCRIPTION 

24 CHANNEL COMMAND CENTRE CASED 
UNCASED 
PLUG IN 4 CHANNEL SOUP STATE MONTIRO MODULE 
PLUG IN 4 CHANNEL RELAY CONTROL MODULE 



£34.95 

£19.96 

£6.50 

£7.50 

P&P1.9S 



TOTAL 



Please send cheque/ postal order to Next Computer Systems for 

C 

Availible for Spectrum, Jupiter Ace + other computers shortly, 
send for details. 

NEXT COMPUTER SYSTEMS, 

88 Harvest Road, Engiefield Green, 

Surrey. TW20 OQR 



154 YOUR COMPUTER, MARCH 1983 






a 



/ 



COMPILER 



£14.95 



• -^Z^r 



OUT OF THE BLUE . . . 

Come three awesome additions to the Softek range of Sof,„ Ware. 



$OFMON 

The ultimate monitor/ disassembler/ machine 
ccxle loader for the 2X Spectrum. Sofmon 
has 25 functions, including modify m HEX or 
ASCII, more blocks, cielete or insert bytes. 
HEX- DEC and DEC HEX conversion, fill, 
display registers and nine breakpoints^ And 
uniquely, as you enter HEX Sofmon will 
instantly do a full disassembly into Z80 
mnemonics! Almost Mkc having ao 
assembler. For 16K or 48K Spectrums. only 
C9.95 including manual. This program is way 
ahead of all competition. 



SOFKIT 1 - A fuH programmer's aid 

This toolkit has every feature you could ever 
need- The fullest renumber routine available, 
coverifig GOTOs. GOSUBs. RESTORE and 
LINE. Search and-replace ar>y character, 
keyword, etc. Delete program lines singularly 
or in Wocks. Display the variables, and list all 
lines containing any given character, phrase 
or keyword it even offers the only TRACE 
facility for the Spectrum? Ideal for developing 
programs to be compiled as it removes 
REMs, changes lower to upper case {ami vice 
versa) and displays program length. 
Incredible volume at f9.95 including manual. 
(16K or 48K Specirums). 



SOFKIT 2 - The complete gra|>hics 
kit 

This astounding program off(?rs instant 
changing of INK or PAPER, pixel or 
characters scrolling (the fastest available), 
colour scrolling. PAINT, separate 'windows' 
which can be scrolled independently, 
characters printed with user defined vertica! 
and horizontal magnification. It even allows 
storage of screens' in memory for cartoon 
effects, and the creation and display of 
Spriielike graphics. Designed to work with 
our compiler, this kit is unbeatable at C9.95 
n6K or 48K SpectfumsK 



These new additions to our range, as weU as our best seHing Meteofoids, Softime. Zolan Advertture and 3D Mazenture Dragon's Lair, 
are available from your local software outlet. If not, let us know! If you can't get our Sof^^ Ware locally write to us at: 

SOFTEK SOFTWARE, 329 CROXTED RD., LONDON SE24 



WANTED GOOD M C PROGRAMMERS FOR SPECTRlJM BBC DRAGON VIC ETC. 



GENEROUS DEALER DISCOUNTS 



YOUR COMPUTER. MARCH 1 983 1 55 



Push your Sinclair to the limit 



ZX81/SPECTRUM 

ARCADE GAMES 

_.,--^ ZX INVASION FORCE 

^^%^^,„^ Use your skill to fire through 
V-*-**""*"^ the energy band to destroy 
the menacing alien ship — 
^^....^ £3.95 
-<^\|V| SPEC INVADERS 
MpV^ SPEC GOBBLEMAN 
\^,--'^-'*'^ These exciting high- 
speed classic games 
incorporate hi-resolutiongraphics and 
sound to bring you the best in arcade 
action at only £4.95 each (16/48K) 

_^^,,^ SPEC FROGS/SHOWDOWN 

f^Cp\jU *^^P across the dangerous 
•jj,,*--^*'*^ road avoiding the lethal cars, 

then lorries. Go back to the 
wild west for a gunf ight battle amongst 
cacti and wagons. Features include 
western music. £4.95 

^^,^..^1^ NAMTIR RAIDERS (ZX81) 
^•"C^vM *^'9^ speed, quick action 
f^^VjJ^ arcade game with four 
■J^*.--''^*'''^ separate groups of attackers. 
£3.95 

Gobbleman also available for 2X8 1 at £3.9$ 



THE ULTIMATE ADVENTURE FOR THE 
SPECTRUM/ ZX81 for only C9.95 




UTILrTIES 

TOOLKIT . 

Nine powerful new functions for 
-yourZXSl (including re-number 
■ (inesigoto. gosub). program merge, 
string finding and replacement. £5,9S 

SPEC BUG 

A 30 in 1 machine code tool and disassembler 
for your 2X Spectrum. £6.95 

ZXBUG 

A 30 m 1 machine code tool and disassembler 
for youf 2X8 T. £6.95 




Improve your machine 
code programs with this 
new 48K Spectrum 
Assembler 

Just released by Artie, this new professional 
quality assembler is also available for tSK 
ZX81 and features:— 

♦ WordprocessoMike text editor. * High- 
speed, versatile twopass mnemonic 
assembler with labels and detailed error- 
trapping. Will assemble to any address. 

* Essential support facilities such as 
memoryedit. register inspect/modify and 
search for de-buggtng. ♦ Full output to 
ZX-printer. ♦ Memory-status 

report and comprehensive _ . ,, ., ori rur 
user-manual ONLY t-^.^TD 

ZX81& SPECTRUM 



SPECTRUM 

MICRO CHESS 

The onty Chess program for d 16K or 48K Spectrum 

Allows all legal moves, casieiling; en-passant 

and pawn promotion 

Options to play black/or whtte. Sets 

board m any position. Fud colour 

and graphics display. 

ONLY 

£6.95 



NEW LOW PRICE « 

^ GAMES ^ <h. 
O ONLY £5.95 for ZX81 
and£6,95forSPECTRUM 

INCA CURSE (Adventure B) 

In a jungle clearing you come across an 
ancient (nca lenr>ple. Your mission to enter, 
collect the treasure and escape alive. But 
beware! includes a cassette save routine. 
SHIP OF DOOM (Adventure Q 
You are unavoidably drawn to an alien cruiser. 
Can you reach the control room and free 
yourself? Or will they get you first? includes 
a cassette save routine. 

ESPIONAGE ISLAND (Adventure D> 

While on a reconnaisance mission your plane 
loses control and you are forced to land. 
Can you survive and escape with the island's 
hidden secret? 

PLANET OF DEATH (Adventure a* 16/48K 
You find yourself stranded on an inhabited 
alien planet. Can you reach your ship and 
escape? 

mbie.\ ZX FORTH 



s^^t^ 



for SI 



Supplied on cassette 
_ with editor cassette, 

user manuals and keyboard overlay. ZX Forth 
combines the simplicity of basic with the 
speed of machine code nfi\A/ £14. Q*> 



RULES 
AVAILABLE 
FROM ARTIC 

Your eccentric father 
has leU you £10,000 in his will in order to ciatm your 
wir>dfall you must solve twelve clues and ^arn 
access to a hank account in which the mor^ey has 
actually been deposited. Be the first to a ack the 
puzzle and the prize is yoursi Plus you wll win two 
tickets to the city of the secret KRAK»T^*'^ault 
tocatior) The Prize money is increased weekly, A 
telephone number will be supplied so you have the 
opportunity to fincJ out iust how much you COuld win. 

DON'T MISS 

YOUR CHANCE TO WIN 

A FORTUNE! 





■SPECTRUM 
CHESS 4>K 



SPECTRUM 

INVASION 
FORCE 

A pODutaf arcade oame tor 16K or 48K Spectrum 

Fires through the force tieid tc destroy the 

menacing alien ship. Sounds easy?? Two levels of 

play — f>ormal or suicidal. Full colour. Sound and 

hires, graphics 

NOW ONLY £4.95 



A 

GREAT 
CHESS 
GAME FOR 
YOUR ZX81 
OR SPECTRUM 
ZX CHESS I 

Very popular machine code program, with six 
levels of play aad an analysis option. Available 
fofZX8l.£6.50 

ZX CHESS II 

A new improved version, with a faster response 
time, seven levels of play, analysis option and in 
addition a recommended move option. £9.95 

ZX IK CHESS 

Anincredibiegame 
in IK for only £2.05 



featuredonn^ 



AAAAAAi 




SPECTRUM 

VOICE CHESS 



TliiS mcrfedi&se progrdfn talks you 

through your game. 
It t«)ls you *tft move, recofnmends a move, and 
contains a range of facetious com men is. The gar- * 
IS based on the highly successful 2X Chess II ^r.r. 
i5i offArod At thi> Cr^''*sSmas of fpr p^re of £9.95. 

sWc'r^LWir.lirn'oJ^VnTyVsVs"""" 



ALWAYS AHEAD WITH ZX81/SPECTRUM SOFTWARE . 

1 ^^ I 



Cheques & RO. made payaDie lo: Aittc Computing Limited Dealer enquiries welcome- 
Please state whether your Ofder tslorZXfli or Spectrum Sef>d S.A E. (Sin x 9jn) tor catalogue 



RTna 



ARTIC COMPUTING LTD. 



I 



396 JAMES RECKITT AVENUE, 
HULL, N. HUMBERSIDE, 



To: Artie Compuimg Ltd , 396 James Reckitt Avenue, 
Hull. N. HumOerside, HU80JA. 

Please supply 



Cheque for total amount cnctosea. 

Name . 

Addfess 



YC 3 



1 56 YOUR COMPU i ER MARCH 1 983 







From M. E Ev*m ih* tvthotf 

01 ttH htgirtv iccliimtd 

30 MONSTER MAZE #fvd 

30 0EFeN0ER 



4! , . j^:^ ^33lii^rji3iii> 



3a TUNNEL i16K ^ 4SK VfriKinton ont Upt) 
Whtl li«f tf) t>»« d«pthi of the tufir^et^ fl^p^tn^ bm, I 
tt^pmg toa4i, tcuffymg r«Ti. crjrwUfi^ iptdtrt. All *pp**t I 
liv« in ih« 3D TUNNEL «f il wf««ct ^boul, Wc Iriit th« I 
iMt obi*<X to your im«afn«t»on {Not in 16K vert»o«>K [ 
PfKt CS-95, ipecitl introductofy oHff 4t f 4 9& onlrl | 
F«brujfy 28tK 







^■M 



s'SKSPffDei/ffl 



GAMES 

FOR THE 

SPECTRUM 



ESCAPE ( rfqmrti Of^iy 16KI 

C»n you f-.liCKi« Uom Xf\t dinouMr mleittd mut'* 3P 
gf Afidtttrxl vivvy provt<5*i dinouuri with tht opportunity 
to Hi<k bfhind th« hfdgti Or to lOjr Ovtr th«m to iv*oop 
dow(\ on yoti "Or>e of tht b*ii «nd mott onijifiil 
S4met ^e h»*e H«n for Ihe Sptclfum to far" 
SINCLAIR US£8 Pricf €4,9& 



,- ,iX, 



GR'SI^'SPECTRUni 



u 



For instant CREDIT CARD Sates by phone only ring 

01-9309232 

Orders to: NEW GENERATION SOFTWARE deptlQ 

FREEPOST (BS 3433) (no stamp required in UK) 

OLOLAND COMMON, BRISTOL BS15 6BR 

Please send s.a.e. with all enquires and for lists of stoclc- 
ists. TRADE ENQUIRIES WELCOME AT ADDRESS 
ABOVE. 



TAGRAPH 




PLOT WINDOW 



fi/ow stspphtd with offset cslti>rsted vAndcw espectolty d^sign^d foe 

ZX 
SPECTRUM 



place ymir drawing etc. in the Victa^raph and yov are ready to p<oi and draw, using the 
movable window rnask and otfsat co- ordinate window. 

With easy to eotl scale and EASY FINDER to he!p with negative and zero numbers. 
Combine PLOT, DRAW and CIRCLE to advantage with V«ctagraph-Ptot Wmdow, 

UK only 

Total price ZX Secirvm €7.50 Atari 4/800, Dfagon 32 C7.00 

Please state WHICH - Cheque/ P.O, to Victa CeramHs, Tel: 088W 2426 

VICTA CERAMICS (YC) 
6A BOW STREET, RUGEIEY. STAFFS. WS15 2BT. 



SPECTRUM SOFTWARE 
FROM OZ 

Special Packages from OZ SOFTWARE for the 
16k & 48k SPECTRUM 

Package 1. MAOCHICKEN 

A machine code game that is as exciting as frogger. MAOCHICKEN has 

automatic increasing levels of difficulty. Supergraphics, The MAOCHICKEN 

must avoid the traffic, foxes and jump on and off rapidly moving logs to get 

home. You are warned that this game i$ not for the stow. 

Packago Z PILLMAN €r DESIGNER 

PILLMAN:— Our vorsion of a poputar arcdde game with nasty spiders to 

outwit you. Six levels of ptay. 

DEStGNER: ■ This utility program dltows you to design, save and use your 

own graphics on the Spectrum Keyboard. 

Package 3 "FROGGY" 

A machine code garr^e suitable for alt ages. Guide your frog across the busy 

road, but beware of fast moving cars. 

Package 4. TRAINMATHS 

A teaching pfogram for all ages. With ADD SUBTRACT MULTIPLY and 

DIVIDE options. Uses helpful graphics to stimulate your>g children tr^to 

getting the correct answers. Dare aduks try it? 

P«ckdg« 5. KANDYMATHS 

A collectk)n of useful mathematicat solutions to the following: — 

simultaneous equations. Quadratic equations inctuding complex roots, 

Mean & S/D< Linear Regression, Mortgage Repayments with easy 

alterations to the variablos. 

Package 7. SPECSOUNO 

This program ai ows you to ci cato arvd save rrvichinc code level sounds. The 

package olso has a library of 20 sounds for you to listen to and use. The m/c 

sound routines you have created can easily be added to your own garT>os. 

The program has many other features and is interactive throughout. 

Package 7. OESIGNER 

A special offer on the DESIGNER program in 2 abov« - for only £2.96. 

ALl PROGRAMS FIT THE 16K &48K SPECTRUM. PACKAGES 1 to 6 ARE 

ONLY €4.95 each. 

SPECIAL OFFER A setf adhesive label that can be attached to the 

Spectrum. It contains references to useful PEEKS €r POKES. Saves time 

lookir>g through the manual. £1.56 each. 



Cheques/P.O. crossed and payable to: OZ SOFTWARE, 6 ROOMELt RO, AINTREE. 
LIVERPOOL L99AH. 



■ Please send m« Gl 02 C3 G4 G5 Z]$ G7 CLabel 
I NAMF 

I ADDRESS 



PI&BSB tick box. 



I 

I POSTCODE 

I I enck>se a cheque/ P.O. for £ 



I 

I 

_YC3/83 I 



Extend your ZX81 System: 
Add Memory that won't Forget! 



ADO YOUR OWN SYSTEM UTILITIES 

BUILD UP A LIBRARY OF MACHINE 
LANGUAGE SUBROUTINES 

UP TO 8K NONVOLATILE RAM 



^ USE HM6116P CMOS RAM 
OR 2716/2732 EPROM 

^ COMPATBLE WTTH 
I6K RAM PACKS 







^ *'- 



INTRODUCTION 

Trvs m«fr<¥V tW4#d n <> »» y>»<l lo \M tfw tr«vtp«f«<il W, 
CAOCh 0« mf^nory (Irc^ a lo tCK} m a ZXai«<4< syM»m 
TN» ««« of fTwmory « 4n idMi pMct lO ttor*. «rth«r p«tf . 
mjmtniry o# f«ntpofilily. rviKfWM l«nQg«go routtr>M or 
cmm wtiicn af» lo cw Ms«i tiy ir^ BASC «v«l#<D Swcft 
rovonrs cou*d b«. lo* fti^fecnpio 

• liv 9f4^jnjci roufi^oi 

• c^itAom m*ih«m«t<«* or »iatn*c»l h^^ctor^s 

• &na^ cod«/ ASCII ooo\««»'On itHMs 

• OCtaV<toCimal/h#« COOvtiUOn I9ut(fi0ft 

• rrtcnupr »*fvicing roulinvs 

" UO lorvoog louinm tot control appK^tiOoa 

« « d«c 0fi«filirt9 itXiSt ct uCTicf amfwiOQ/rmm lyu^m 

• ipooch lymhtfUfc i«mm«s 

« aiO^KiraH BASiC oo<nmvKM 

• £PRCHk^ pfogf aitwfMio «n^ v«nfr ro«4n«« 

A s^m0* tiQmi (34ptify iOu<in« «nd proc«c}iir«« for ikvwq 
utAt»«5 on ikp« are inciuoec w^n ttw *n 

Th# it%t o* HM4n6P 2K CMOS RMI m^rrtocf iCs w*ry 
:ne^ own r«««rv« poww auppty tji^jnw iruu routmoi <v&iv*d 
^ tlio HAM Jf • rtofwolaii^ - itt0 AaM tttjMnt 4% n^ofrtory 
Cv«n MfttA ilw 2X01 « swMchM oil ot r«is«i Mortovw bt 
mi^ RAM, Itw rouftiMtt fO^» 9Mt« m Vtm trmfnotf m% t^imt 
«nodiN4 Th*blhHimc«iMpphMiM«itfi*tN»4rdMi(Tuir 
l»€t %JHtc^€\i rvMcv* povuPt lor abou r«n iT>oc«h» lo* 2K Of 
!o* utiovii r*o fTorum lot A iuiif popuU'rtM tictjro A co*v 
o«ctor IS fnaa« ava4«eAe (0( *n antufMn* wnit'trm i^^ppt^t 



s> 



WHh Wh^ COJIfO rt'ft no lon^tr niCMMiy lo pt*tM your 
rnKtMw lAnguiQ* rt^^rftin^s 4fi ntiA tt»i*fntK<%. m i:n«^ 
viriibl»k 01 b»vO^ RAMTOP YOucantMjidtKytrMid*^ 
VbfMV 0( mncfww ut*t«» to<r y*« t>y yuyf 6ASC f^^m 

One* your syii^rn ubH>^ «n(J ciri«<f rnttdhit^ Mngui^ 
tQtjbfim *f« ^siJCAihed you c^n it yo^ msn, r^piaco ih* 
eil«» CMOS RAMI wth ^7t« o< 2732 EPROM 1 

OTHER OPTIONS 

Th« b04f d can ttq jump«f piogf #mm«d lo occupy mf om 
ol iri« louf aK Mxlis d m«rriOfy m tfv* (krii %K Youc^ 
for •rdjtfTtplo. mocHy tn« SINCLAIR cptxMHn^ if^tom 
AftOtAtf n«(y lh# b04^! « ^ b« uMd M fytl*<n/u«^ RAM 

ASSEMBLY 

Coop^* si*ptv.*l«p tntif tactions m • t46 ptg» crgmMl 
maito <iai«fn*>'y qI iTw tx)«rd fl«y ConsttKtion i<i*** Oo 
|««en OTIC .*n^ tiK> hoj"* th« krt (pKluroa ifto*»> o com 
pivt* wAfi A i»%a*9fima Mtdof-nmsJuM ptmiwo otfcurf 
tMMtfd, JK c^a^'dcttc^ fMftKnt. ir«niftWo<t* foefc4t». ooriH 
piACtors. <ii4ogriil«di.vci*lt.arHiirMlthiwinc«li Th« board 
i» «uftpli«K] wtf) ont ?K CMO!v 6n$P 3 a«M — « Witt iC^ 
cornod«l« irirM mof « fo< ^ 1C4.M ot 8K 

HUNTER ELECTRONICS, 

KCNWAY. RAYMOf^OS MIIL AXMtfJSTEA. DEVON 
S^a cr>ech or oionay order tor gi^ dS ptts Ct dS tftfpcig 
dfvt nantT^n^ feo »« AddiMft bolow Trw pr«M0 circifl 
boaro nfisn IN; nsifuei«n marHiof o ^^autm MpvAMiy 
(or CiOOOpo«;pA<3 



HUNTER ELECTRONICS, PO. BOX 5. AXMINSTER. DEVON EX13 5AS 



YOUR COMPUTER, MARCH 1983 157 



Q.E.D. SYSTEMS 



the producers of high quality software for your 
SPECTRUM, DRAGON, APPLE II and ORIC. 



THE VARIETY PACE 25 specially selected programs to 
realise the potential of your new micro* 

Spectrum, Dragon, Apple 11, ORfC £4 . 95 

(less than 20p per program!) 



THE VIDEO CHALLENGE These are not just any games 

by Q,E,D. quality action packed programs. 

Spectrum — Photon, Apes & Ladders, Microthello and 

Phantoms only £5.95 

Dragon — Photon, Link-four, Microthello and Phantoms 

, only £5.95 

Apple II — Grand National, Star Trek, Link-four, 
Microthello . , , cassette £5.95, disc £7.95 

MACHINE CODE ASSEMBLER and UTILITIES Realise 
the full potential of your micro by writing your own 
machine code routines. 

Spectrum, Dragon .... £6.95 

(includes full documentation) 



COMPLETE HOME MANAGEMENT Plan all your 
financial affairs with this Q.E.D. quality system. 
Features include budget creation, maintenance and 
balance of all accounts Tine, credit cards). Full monitoring 
of expenses against budget and complete expenses 
reporting. This system is supplied with full documentation 
and operating instructions. 

Spectrum, Dragon, £9.95 

Apple /I (disc) £12.95 



Calling all designers! Q.E.D. pay generous royalties for 
high quality programs and routines. All enquiries are 
treated in the strictest confidence. Why not send your 
programs today (details are available on request, please 
include s.a.e.). 



All programs are supplied on quality cassettes, unless 
otherwise stated. 



Please send me on cassette/ disc 

THE VARIETY THE VIDEO 

PACK CHALLENGE 

MACHINE ASSEMBLER 
FUTILITY 




COIVIPLETE HOME 
MANAGEMENT... 



for my........... MICRO with. 



memory 



I enclose my cheque/ postal order for C. 
(payable to Q.E.D. Systems). 

Name 

Address 



Q.E.D, SYSTEMS 

2 Sefton Gdns, Ashton Green, Ormskirk^ Lanes. 



L39 6RZ. 



YOUR QUICKLEARNi 
WAY TO BASIC 
OR COBOL 



> 



IN YOUR OWN 

HOME, 

IN YOUR OWN 

TIME, 

AT YOUR OWN 

PACE. 



Learn computer programming quickly and easily | 
through the renowned ICS "Open College" 
system, taking the course at your own pace and 
in your own time. 

Use the famous ICS study texts, backed up by 
your own expert tutor, and learn computer 
programming, the proven way, with ICS home 
study. 

Courses: 
Introduction to Computer 

Programming 
Programming in BASIC 
Programming in COBOL 

IcAccj ^Cr 

Apofovcd by CACC Member of ABCC 




i Please send me your prospectus on Computer Programming 
I IflVQ Name^ ^. 



Address. 



l,//IUli\\\ ^^^^ ^^ Depi' EE349 

ICS School of Computer Progfammmg 
160 Stewarts Road, 



I 



luliKalon 



01 622 991 1 



I 
I 
I 
I 



- L'nrpi.Tatinn Loncion SVV8 4U J (jU tsuursi I 



JUPITER 
ACE 

Forth programs for the Ace: 

Tape 1: PEEKER (disassemble ROM and RAM \n Decimal, Hex, 
ASCII Character & Binary) (32K) £4.50 

Tape 2: SKETCH (user-definable screen cursor, with tape save), 
EDITOR (for text, with tape save), DEMO (of Sketch), NIGHT 
RIDER (simple game) (3K) £5.50 

Tape 3: 3 FAST 3K GAMES (in m/c): Appleater, Parachute, 
Meteor Cruise (3K) £5.50 

Tape 4: 4 CHALLENGING 3K GAMES: Saucer, Driver, Maze Para 
(3K) £5-50 

Tape 5; FROGGER (needs 16K) £5.50 

Tape 6: TOOLKIT (m/c routines inc. scroll up/ down /left/ right 
with/without wrap, invert, fill screen, etc) (16K) £7.50 

Tape 7: CHARACTER DESIGNER (design your own characters) 
(16K) £6.50 

ADAPTOR FOR USING 2X81 ADD-ONS (kit) (club members 
only) £7.50 

ACE USER: magazine, £1.25/issue. Free to club members. 

NATIONAL JUPITER ACE USERS CLUB: £7pa. 

All prices inc p&p; Club members deduct €1 per tape. Cheques 
payable 'R emsoff plea se. Allow 27 days delivery 



REMSOFT 
18 George Street 
Brighton BI\I2 1RH 
tel: 0273-602354 




1 58 YOUR COMPUTER. MARCH 1983 



(( 



DRAGON 32 
NEW FROM 

TROJAN 

SPACE TREK 



> 5 



Space Trek is an absorbing space wars game in real lime 
which can be played in any of four levels. Special features 
include: Onboard battle computer. Long range galaxy 
scanning. A galaxy containing 100 quadrants. Impulse and 
warp drive speeds. Shield control and status reports. 
THIS GAME IS A MUST FOR DRAGON USERS. 
APPROVED BY DRAGON D.ATA LIMITED. 

THE TROJAN LIGHT PEN 

Plugs into Joystick Port 

Supplied with cassette of instructions 

A simple to use device for micro fans 

Send to: TROJAN PRODUCTS 

Dept. PCK 

166 DERLWYN, DUNVANT 

SWANSEA, WEST CLAM SA2 7PF 



Please send: 

Space Trek — I enclose cheque/P.O. for £7,50, 
Light Pen — I enclose cheque/P.O. for £10.00. 
Both prices include post & packing. 



MR/MRS.. 
ADDRESS. 



TRADITIONAL GAMES 

FOR YOUR 
SPECTRUM OR ZX81 

Qu/et! Sociable! Easy to play! 





ROULETTE (Spectrum 48K) £4.95 

The best version of the Monte Carlo game available. 
Full colour betting table on continuous display. 
Most betting combinations accepted. 
Up to 4 named players. 

Automatic debit &■ credit of displayed bank accounts. 
GAMBLING TAPE (Spectrum 16K) £2.95 

Fruit Machine - holds - nudges - gambling feature. 
Poker Dice and Slippery Sam. 

CHILDRENS COMPENDIUM (Spectrum 16K) C4.95 

(ZX8116) £2.95 

Ludo, Snakes & Ladders, Beetle — Up to 4 named players. 
Noughts £r Crosses and Fox & Geese, where you can play your 
friends or the computer. 

Roulette B Gambling Tape £6.95 

All 3 Spectrum programs £3.95 

All prices include pBp. Money back guarantee, 

DYMOND SOFTWARE 

DEPT YC, HOSPITAL ROAD, 

ANNAN, DG12 5HP, DUMFRIESSHIRE 



BBC MODEL B 

(or Model A with 32K) 



£7 



CARCHASE 

A superb new car chase game. 

TOTALLY ADDICTIVE. 

This game features rolling track Colour and sound 

effects. 

ESP £3 

Test your ability to predict future events with this 
program. With colour and sound. 

ELIZA £3 

Have a conversation with your computer 
Psychiatrist, 

SPECIAL OFFER ALL THREE £10 

Mail order only please to: 

Ross Software 

Dept YCl, 

44 Premier Avenue, 

Grays, Essex RM16 2SD. 



THE NEW AND UNIQUE 

C.A.D. PROGRAMME 

FOR THE BBC(32K) 

AT A VERY AFFORDABLE PRICE 

fcJeol fof teachers, desfgners, artists, technical drawing and numerous other 
apptications incKiding vouf own form and stattonerv design etc. 
This progfaninrte mu$t be seen to be appreciated - your imaginatior) is the only 
factor to limit its individual applications, 

• Modes J ,2,4,5 (can be changed when programme is running). 

• Muittpie display of arrays enables infinite convplexity. 

• FUNCTIONS: Line, rectangks, triangle, drcte, text {upper 8f>d lowtr case) and 
cok)ur pallet (8 colours <rvd ftashingl. 

• ORAWrNG AIDS: AJignmeni grxf, cifcle copy, delete, free memory^ purge 
memory, variable cursor Speed, clear screen ar>d redraw. 

• Shapes can be filied or outlined (no need for Frfl Routines). 

• Save and toad to tape in about 20 seconds. 

• SPECIAL FACILITY - Rubber band mode - A very flexible and variable line 
drawing facility - niust be seen. 

• Free "rodrav/' routine to enable the pictures created to be displeye<f in your own 
programmes, 

• Grafkey and Grafstik. Vef*ior\$ availble for keyboard - Gfofkey and A/vy type of 
joystick - Grafstik. 

Fantastic Value only £7.95 inc. p&p 

DISK £10.95 



CLARES 

222 Townfield Road, 
Winsford, Cheshire CW7 4AX 
Tel: 06065 51374 



YOUR COMPUTER, MARCH 1983 t59 



GEMINI 
SOFTWARE 

ZX81 (16K) SPECTRUM |48K) 
STARTREK 

Features an 8x8 Galaxy, Kfingons and Starbases, short 

and long range scans. Torpedoes and Phasers, Computer 

etc. 

PLUS Normal or Hyperdrive: choose your speed but 

watch the energy level. 

Galaxy Map: keep track of where you have been. Also, 

shows whether any Klingons remain there, and where 

the starbases are. 

Visual display of Enterprise's position and movement. 

Visual display of photon torpedo. 

Messages from crew members. 

5 levels of play. And much more. 

Cassette plus full instructions. 

ZX81 £4.95 

Spectrum £5.95 (colour and sound too) 

Sae for other programs, 

Gemini Software 

36 BADMINTON RD, LEICESTER LE4 7RQ. 
TEL (0533) 64915 



ZX SPECTRUM & ZX81 
EDUCATIONAL SOFTWARE 



Spectrum Junior Education £5.50 

Use your Spectrum to help your children with their school work. 
This cassette contains eight attractive, easy-to-use programs for 
the 7 to 11 age group. 

Topics include English comprehension, spellings, homophones, 
junior science, maths and history. 

* Entering your own questions and answers allows you to adapt 
two of these programs for exercises in any subject area. 

* Moving colour graphics and sound are extensively used to 
improve motivation. 

* Use the "draw" program to produce pictures, maps and 
diagrams. 

Suitable for the 16K or 48K Spectrum. Program notes are 
supplied. 

0-Level Chemistry (CI) K.50 

This cassette contains four clearly presented revision/tutorial 
programs. The subject matter has been carefully structured to cover 
the most important aspects of: 

* Elements, compounds and mixtures. 

* Structure, bonding and properties, 

* Redox, electrolysis and the activity series. 

* Acids, bases and salts. 

48K Spectrum and 16K ZX81 versions of the cassette are available. 
Please specify which you require. 



Professional Computer Assisted Learnmg materials from: 

CALPAC COMPUTER SOFTWARE 

108 Hermitage Woods Crescent, St Johns, 

Woking, Surrey GU21 1UF. 

Overseas orders: £6.50 (SI 1.60) per cassette; includes AIRMAIL 
postage. 



Why should games players have all the fun? 

SUPERPLAN FROM 
VIDEO SOFTWARE LTD 

For 48K ZX Spectrum 
We take ZX computers seriously 

Serious software which you will enjoy using 



With SUPERPUN you can put 
your ZX Spectrum to serfous use 
in the home, school, club or small 
business. 

Create and update an analysis 
sheet or spreadsheet within the 
Spectrunn's 48K RAM. 

Save the chart on cassette. View ii 
using the TV screen as a window, 
update it from the keyboard. Print 
it on your ZX printer {optional. 

We have delayed advertising this 
product until now to ensure 
availability. 



• Machine coded scrolling with 
user variable windovvs. 

• Binary coded decimal arithmetic 
(BCDJ. 

•Variable column width. 

• Up to 52 columns. 

• Chart capacity exceeds 40000 
digits. 

• Full colour display. 

•"Flashing box" posiitoning under 
keyboard control 

• Arithmetic functions + - * / % 
(and one or two nriofe)- 

• Audit trail of all entries. 



f,^ VI DEO 

^J^ SOFTWARE LIMITED 

Stone Lane, Kinver, 
Stourbridge, 
West Midlands. 

Tel: 038-483 2482. 

SAE for dat3 shmt 



SUPERPLAN. The complete do-it- 
yourself analysis chart generator 
and processor. £12. 

SUPERPACK r Four ready made 
charts for business — sales 
daybook, purchase daybook, cash 
book and petty cash book. 
Complete with SUPERPLAN 
processor but without the 
generator. 



£7. 



Cash with order for immediate delivery, forces include VAZ P* & ^- 



Simonsoft 

Specialists in high quality 

software for the 
BBC Microcomputer 

DISASSEMBLER (A/ Bl 

Unlock the secrets of the BBC's ROMs and nnachlne-code 
progranns. The Simonsoft Disassembler includes a host of 
features which make it the most powerful, yet flexible and easy 
to use. Disassembler for the BBC Microcomputer. 

Designed as the first of a suite of compatible programs which 
form the essential tools for machine-code experts and beginners 
alike. 

FEATURES: - 

Five Modes of Operation:— Ranging from — memory dump 
with ASCII character equivalents — through line-by*line dis 
assembly in BBC standard format — to full automatic 
disassembly with labelling of all jumps, branches, subroutines 
and data. 

User Definable Labels:— Can be attached to any memory 
location be it code or data. Automatic labelling can be redefined 
by the user, 32K machines can hold over 2,400 labels, 16K 
machines hold nearly 5001 Operating system entry points and 
vectors are automatically labelled on loading. 
Disassembly Aids:— Two additional aids to disassembly are 
included: 

i). A map of which areas of memory hold code, and which hold 
data. Up to 72 separate areas of code can be defined. The map 
is automatically generated during automatic mode, 
ii). A stack of useful addresses to aid line-by-line disassembly. 
Output to Printer and Tape:— Disassembly can be listed to a 
Printer, or dumped on tape in Basic 'Exec format and 
subsequently incorporated in other programs. 
Easy to Operate:— Menu driven program with full instructions 
in a "Help" program and single key commands. 
Without doubt the best Disassembler on the market. 

BBC DISASSEMBLER (A/ B) C6.S5 

(lOOK S/S Disc Version . . . £9.95) 
Prices fully inclusive — cheques/ P. O's to: 

Simonsoft 

Front Street, Topcliffe, N. Yorks, Y07 3RJ 



160 YOUR COMPUTER, MARCH 1983 



m^ I. J.K.'s R 

oUHLirrv 



OJIDB 





\m MODEL A/B 

Cassette 1 : Star Trek/Candy Floss (very popular) 

£6.50 

Cassette 2: Family Games (hours of fun) £4.50 

Cassette 3: Mutant Invaders/Breakout £6.50 

Cassette 8: Model A Invaders (M/C) £5.50 

iit#^ MODEL B (or A+32K) 

Cassette 4: Beeb-Beep (Super Simon Game) £4.50 

Cassette 5: Beebmunch (full colour Munchman) 

£6.50 

Cassette 6: Super Hangman (animated, educational) 

£4.50 

Cassette 7: 3D Maze (fast and intricate) £4.50 

Cassette 1 2: Flags (Countries and Capitals) £4.50 



j[|#^ CASSETTE 13 - HYPERDRIVE 

A new, very addictive machine code arcade game. 
Guide your laser tanks around the network of 
passages destroying the drone Aliens- but beware, 
evil OTTO lies in wait! 
Only £6.50 inc. For MODEL B (or A+32K) 

1114^ CASSETTE 14 - STRATOBOMBER 

Another new highly colourful machine code arcade 
game. Can you keep the enemy fleet at bay long 
enought to destroy the nuclear reactor of the rogue 
Star Ship before it destroys your home planet? 
Superb graphics. 
Only £7.50 For MODEL B (or A+32K) 



iin#^ CASSETTES 

Contains model B Invaders, A superb feature 
adaptation of the arcade *Space Invaders' game in 
machine code and hi-resolution colour graphics for 
the BBC Micro model B (or A+32K). Play normal 
game or choose from the many options including 
Missile, Bomb and Invader speeds, invisible Visible 
and Shields no Shields. Quite simply the best. 
Only £7.50 for MODEL B (or A+32K) 

itt^ CASSETTE 10 
WORDPRO. Cassette based word 
processor for either Epson or Seikosha 
printers. Features right hand justification 
alter, insert, delete, pages to tape, printer 
mode changes from v/ithin text line etc., 
etc. Complete with manual. 
Only C10*50 inc. for MODEL B 

(or A+32K) 

mm^ CASSETTE 11 

ATLANTIS. The superb fast action arcade 
game written in machine code to illustrate 
to the full the machines fantastic colour 
graphics and capabilities. This game 
includes all the usual ATLANTIS/ 
SCRAMBLE features. Guide your 
submarine Nautilus along the undersea 
landscape and through the caverns 
avoiding mines, depth charges, rockets, 
jellyfish, serpants etc. 
Only £7.50 inc. For MODEL B 

(or A+32K) 



fie^ CASSETTE 15 - LEAP FROG 

The fabulous Irogger' arcade game reaches the BBC 
micro. Superbly written full colour machine code 
version for the Model B (or A+32K). Help the frog 
cross the road avoiding the vehicles travelling at 
different speeds, and cross the multi current river to 
reach the safety of the lilly pads. The game gets 
progressively harder- perfect for arcade addicts, 
Ni^ Only £7.50 for MODELS (or A+32K) 



WE'RE EXPANDING 
TOO.. .NOTE OUR NEW 
OFFICE ADDRESS AND 
CUSTOMER SERVICES 




f^ 



ORIC MICRO software ready 



.^v*^ soon. Write or 'phone for 
availability. 




24 HOUR 
ANSAFONE 



UK 

Software 

Limited ^^--"'--'>-'-*^ 



® 




All Programs will run on all 

operating systems 

All software in stock before we 

advertise 

Send SAE for Brochure 



9 King Street, 
Blackpool, Lancashire 

(g)(0253) 21555 



ALL PRICES FULLY 
INCLUSIVE OF VAT AND 
P&P- NO MORE TO PAY! 



rTa-^T 



[DCD0 MICRO GAMES 




It can do a powerful job for yoi 



SPECIAL LIMITED 
OFFER 

Buy just any two programs at £19.95 
' and take one at £19.95 

FREE! 



CASH BOOKS ACCOUNTS 

PROGRAM FOR 

BBC MICRO. . .£95.00 




M^ 



One of the most innovative business 
prosrams on the market. Most serious 
accountancy packages are v/ritten and 
coded by professional and competent 
programmers. The Gemini Cashbook Accounting 
program was written by practising Chartered Accountants and 
coded by profe^ional and competent programmers. This is a 
fundamental difference - 

This practical program is simple to use and will replace your 
manual cash and bank records and by giving you instant 
management iriformation, it may even put your accountant out 
of job! 

With exceptionally exhaustive user documentation, full 
technical back up and product update policy this program will 
increase the efficiency and profitability of your business. Take a 
look at the information this program will provide. 

* summary of VAT information to enable you to complete your 
VAT returns 

* cumulative receipts and payments report anai>^ed over the 
standard profit and loss and balance sheet heading. 

* option for departmental analysis of sales and purchases 

* print out of all transactions 

* journal routine for entering transfers between accounts and 
year end adjustment for debtors, creditors etc. 

* year end trial balance 

* profit and loss account and balance sheet. 

These statements can be produced at what ever interval 
you require e.g. monthly, quarterly or annually. 

Comins soon:- Intesrated Sales + Purchase Ledsers 




. . the systems worked immaculately 
when tested . . /' 
"Mailist is a very professional piece of software 



(Which Micro & Software Review Feb 83) 



Here's a range of software for the independent 
businessman that's designed to hamess the power of your 
micro to delrver the vital information you need in all key areas 
of your business. A breakthrough on both price and 
performance^ each program is fully tested and comes with all 
the documentation t>ack up you need. 



**Gemini's range of software is in the vanguard of 
the releases for 'serious' micro users . . ." 



(WWch Mioo dnd Software Review) 



SPREADSHEET ANALYSIS 
BEEBCALC £19.95 
DRAGONCALC £19.95 




r^e?^ 



FOR BBC AND DRAGON 32. Spreadsheet 
processors have proved to be important 
tools for using micros in business, scientific 
and domestic financial applications. 
Without any programming knowledge at all; you may:- 

* Set up a computerised spreadsheet, with chosen row and column names. 

* Specify fomnutae relatins any row or column to any other. 

* Enter your source data and have the results calculated. 

* Save the results on tape (or disk - BBC) for later reloadlna and manipulatkxi. 

* Print the tatxjlatcd results in an elesant report format. 

* Experienced users may access saved files and write their own repoftins or 
graphics presentation prosrams for the results. 

Some typical applications:- 

* Small business accounting applications, e.3. profit and loss statements and 
cashflow projections, break-even analyses etc. 

* Investment project appraisal ^ anything from double glazing to oil rigs! 

* Comparing rent/lease/buy options 

* Processing the results of scientific experiments or fiekl studies 

* Engineering calculation models 

* In fact, anything that involves repeated re-calculation of results presented in 
tatxjiar or spreadsheet fom^at. 

Program AvailabJIity Chart:- 



r - " 


CklMMW 


tortro* 


;,\*-.vr 








woto 


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• 


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• 


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68CrKfO 
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• 


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ur business at petty cash prices. 





INVOKES AND STATEMENTS . . • fi19-95 

Compatible wrth most micros. See tabic. Ideal for the small 
business. A complete suite of programs together with 
generated customer file for producing crisp and efficient 
business invoices and monthly statements on your line printer. All 
calculations include VAT automatically, and the program allows your 
own messages on the form produced. This program gives you superb 
presentation and saves time on one of the most tedious tasks in the 
office. 

COMMERCIAL ACCOUNTS . • , £19.95 

Compatible with most micros. See table, A gem of a 
program, all for cassette, with the following features:- Daily 
Journal, Credit Sales. Cash Sales. Credit Purchases. Purchases 
- other. Sales Ledger. Purchase Ledger. Bank Account. Year to date 
summar/. A fully interactive program suitable for all businesses. Files 
can be saved and loaded and totals from one file carried forward to 
another on cassette. Particularly useful from a cash flow point of view, 
with an immediate accessibility to totals for debtors and creditors. Bank 
totally supported v/ith entries for cheque numbers^ credits and, of 
course^ running balance, 

MAILING LIST, . .£19-95 

Compatible with most micros. See tabte. A superb 
dedicated database to allow for manipulations of names 
and addresses and other data. Gemini's unique *searchke/ 
system gives you a further ten 'user-defined p>arameter^' to make your 
own selections. Features include the facility to find a name or detail 
when only part of the detail is known, it v/ill print labels in a variety of 
user specified formats. 



m 




□ DATABASE . . . £19.95 
Compatible v/ith most micros. See table. The program that 
everyone needs, the most valuable and versatile in your 
collection. Facilities include sort search, list print if required. 
Can be used in place of any card index application; once purchased 
you can write your own dedicated database to suit your particular 
needs witti a iimitiess number of entries on separate cassettes 

STOCK CONTROL • • . £19-95 

Compatible with most micros. See table. Dedicated 
software with all that's necessary to keep control of stock. 
This program will take the tedium out of stock control and 
save time and money. Routines include stock set up, user reference 
number, minimum stock level, financial summary, line print records, 
quick stock summary, add stock, delete/change record and more. 

HOME ACCOUNTS . . . £19.95 

Compatible with most mkrros. See table. Runs a complete 
home finance package for you v/rth every facility necessary 
for keeping a track of regular and other expenses, bank 

account mortgage, HP, etc. This program also allows you to plot 

graphically by Listograms your monthly outgoings, 

WORD PROCESSOR • . . £19.95 

Compatible with most micros. Sec table. This program 
Ij^ features routines found in much larger and more expensive 
' f packages with a typical word length of 5-6 letters it allows 
for around 1 CXX) words in memory at one time. Ideal for the user who 
requires a simple program to write letters on his computer. Features 
include, block delete, block insert, search and replace, edit text display 
text and more. 





Dealer/Trade enquiries invited - generous trade discounts for quantity 
Special ACCESS card instant sales hotline Tj»I# AOORO R4iLC 
for GUARANTEED despatch within 24 hours ... I d ♦ \9Jbw^£r^ I OS 

24 hr Ansaphone Service. 

All enquiries other than credit card sales to 03952-5832 

Gemini. Functional Software Specialists. 9, Salterton Road, Exmouth, Devon. 



i 
I 

I 
I 
I 
I 

I 
I 



Tick the box for Prosram you require. Prices include VA.T and Package and Postase. 
Please supply the followins cassette software- 
Database „.-.- ,. . ».. -...£19.95 [ 1 

Stock Control »,«,»„„,... £19.95 G 

Mailing List , ,„^«., *. , ™. C19.95 TJ 

Invoices and Statements .. >^ £19.95 U 

Commercial Accoults .» ««.^ £19.95 H 

Home Accounts . ««,„..-«._.- £1 9.95 G 



ZX81 16K[>atabase ™ 

B8C Cash Book a^e^upc ... 
BfiC Disks ' other trtJcs... 
Osborne Dfsk Database , 

Wofd Dfocessof 

BccbcaJc »^^ 

Drasoocak: — «*- 



.» £9.95 D 
... £95.000 
... £23.95 O 
.. £23.95 D 
... £19.95 Q 
£19.95 D 
£19.95 



Namc_ 



Address^ 



Machine Type^ 
rencIosc__ . 



>*emofyS*zc_ 



Make cheques and postal orders po^ble to GenrM Marketins ltd. 



Diners Card Number 



■ •ffl*N,A|%lt4A4 



.Access Number. 



Signature, 



GctninL FUnctkHial Software Specialists, 9 SaKcrton Road, Exmouth, Devon* 




^rr^_ 



A TOTALLY NEW AND ORIGINAL GAME 
FROM SOFTWARE FARM 
FOR16KZX81 



the 




YOUR MISSION 

To penetrate the Witches Defences, Enter 
her Cavern and Destroy her wicked Heart 



THE WITCHES DEFENCES 



STALAGMITES AND STALACTITES which grow across your path. 

Blast a way through with your Lazer Cannon (but -beware - a surprise 

is in store fore you I). 

VOLCANOES to get past alive - if you can! - an ever increasing 

amojnt of white-hot Larva to avoid the closer you get to the witcHes 

cavern. 

VAMPI RE BATS that cling to your ship, making your controls sluggish 

and finally (if you are not careful) dragging you down to your 

destruction. 

CAVE-INS should you hit the side of the cave with your Lazer Cannon 

or Bomb, pan of the roof will cave- in on you — the gr eater the 

landslides to avoid each timeL 

THE NEARER you get to the Witches Cavern, the more of her Defences 

she will throw at you at once. Should you survive all of them (highly 

unlikely) then you must contend with the Witch herself* Avoid being 

turned to stone by her spells white attempting to destroy her wicked 

Heart!. 

* 1 or 2 Players 

* Written entirely in Machine Code • Mystery Score positions to bomb 

* Hall of Fame * 5 Skill Levels 

DESTINED TO BECOME A CLASSIC! 

AND ONLY £5,95 



¥ 



THE SOFTWARE FARM 

CRAIGO FARM. BOTANY BAY. TINTERN. GWENT 



^F 




Data 

Computer 

Cassettes 

& 5V^" Diskettes 

We manufacture computer 

cassettes using batch certified 

HM-1260 tape available in 

fully packaged C5, C 12, C 15, 

C20 and C 1 6 leaderless, or we 

can supply custom wound 

lengths with or without boxes. 

Our SVij" diskettes also 

available ssdd and dsdd. 

Wholesale and Dealer enquiries welcome. 

Contact Nigel Boyle. 

Tel: 1 -223 6955. or write to: 

BlBi Magnetics, Freepost, London SWl 1 2BR 

BiBi Magnetics Ltd, 101-105 Plough Road. 
London SWU 2BJ. Telex: 917732. 




BREAKDOWN 
INSURANCE 



When your guarantee expires, breakdown repairs may 
well involve you in costs of £10/£25 per hour plus parts. 
Insurance is available to provide cover for computers, 
monitors/ tv's, cassette recorders, disc drives, printers 
etc. 

Uses for which cover can be arranged include home, 
business and education. 

Whether your equipment is worth £50 or £5,000 you will 
find the cost of insurance is very acceptable. 

Full details will be sent on receipt of a note of your name 
and address together with the value, age and use of your 
equipment. (No stamp required). 



BALL & CROSBY (INSURANCES - YC) 

LIMITED 

Freepost 25a Park Square, Leeds, LSI 1YY 

SPECIALISTS IN COMPUTER INSURANCE 
MEMBERS OF THE BRITISH INSURANCE BROKERS ASSN. 



MAJOR 



FINANCIAL GAMES 



■for 



SPECTRUM - BBC - ZX81 

Remember those marvellous old board games you used to play? 
Hours of enjoyment are GUARANTEED with FINANCIAL GAMES 

No. T INHERITANCE: A 2 Part game. Prove your financial acumen 
in PART 1 by investing wisely at the STOCK and METAL 
MARKETS; (If desperate you can try the CASINO or the HORSE 
RACES). If you are successful you will enter the world of BIG 
BUSINESS in PART 2. Find the SECRET FORMULA for 
PARADISE COLA; manufacture and market the drink; cope with 
STRIKES, FIRES, FRAUDS, CASH SHORTAGES, ETC. Your 
ultimate aim Is to become a MILLIONAIRE! 

A MAMMOTH GAME PACKED FULL OF FEATURES 

No. 2 GREAT BRITAIN LIMITED: You are PM and Chancellor of 
"GREAT BRITAIN". You must select the Party you wish to 
represent and your AIM is to stay in office for as long as possible. 
You must control INFLATION and UNEMPLOYMENT, maintain 
the EXCHANGE RATE, introduce SOCIAL REFORMS and stay 
POPULAR. The game is split into SECTORS: COUNTRY PROFILE, 
SHOPPING BASKET, BUDGET DAY, REFORM 

OPPORTUNITIES, MANIFESTO, and most important ELECTION 
NIGHT (a telling time). 

A COMPLEX GAME THAT YOU WILL NOT TIRE OF IN A HURRY 
All Games are on quality cassettes with full instructions 

-SPECTRUM 48K BBC32K ZX81 16K- 



£5.95ear 



-£5.95ear 



-£4.95 ea.— 



SPECIAL OFFER: Deduct £1.50 from total cost if you buy 2 games. 

SIMON W. HESSEKDept YO) 

15, Lytham Court, Cardwell Crescent, 
Sunninghill, Berks. Tel: Ascot 25179 



A// orders despatched 
within 24 hours. 



One year guarantee 
Money-back if not satisfied. 



164 YOUR COMPUTER. MARCH 1983 



"^'^'Vw,^ 



s7^.^xv^_^-T:r 



O 



PERSOmL COnPUTERS 



48 JUNCTION Ra ARCHWAY, LONDON N195RD Telex 22568 






W«E20 



NEW 
LOW 
PRICE 
£149.00 



liir 



tbMS 



*mt 



m 



*5 



'.le^tf^ 



VIC PRINTER 
£212.00 

80 Charaaeri per line. 
30 CM<»faaer% per sec., 
Traaor Feed Dot matrix 
punter 



a^^ 



•'* NEW -•W-NEW*'* NEW 'Wt*^-* 



I^E commodore 



VIC SINGLE 
FLOPPY DISK 

^ OUR PRICE £286.00 
! 74K Byte Storage Direa 
I Interface to VIC Off ea 
^Compatibtlity with 

. printer 



VIC -^ ^^" 

^ .Vjij J ^^^ c<issecte 

CASSETTE with 



DECK 
£39.00 



6 programs i 
supplied 



64K RAM 



tfljsic 



S-D 



ixsex 



effect 



"iS^c^o^ 



dii 



OUR PRICE £339 



n^^^ primer * 

HK RAM c^nix }^ f .1, uTTTTT^^^r 

SOFTWARE 

For a copy of our 

VK! IJ$t cont-ainjng 

everything 

you need for the 

VK: computer, ^ 

send us 
t your coupon J 



EG 2000 

PAL VERSION 

* 8 colours 
1 6K RAM standard, 
expandable to 32K 
Extended Microsoft 
colour basic 
standard 
Typewriter 
Keyboard 

CPU:Z80A/2.2MHz 
3 Sound Channels 
40 Columns x 
24 Lines 
* Serial and Parallel I/O Ports 

OUR PRICE £199 



11 



asA£*£i»ii*^*^»a^»-s^^*s« 



« (M o o <• a ^ 



Post to CHROMASONIC Personal Computers, 
48 Junction Road, Archway, 
LONDON Nl 9 5RD 

TERMS OF BUSINESS: All prrces m< \ S% VA! 

Deirvery charged at Cost. Prices valid for cover date or this mag- 

Access and Barciaycard orders welcome. 




/^^r I am interested in a home computer 
'^m Please send me furtherdetails 

n VIC 20 D DRAGON 32 n COLOUR GENIE 

G ADD-ONS D SOFTWARE 

NAMf: . , 

ADDRESS 





YOUR COMPUTER, MARCH 1 983 1 65 





CLASSIFIED 



661 3036 



ADVERTISEMENT RATES 



Copy Date 



Linage: 30p per word 
(Min. 15 words) 
Box No: £3.00 extra 
Linage advertisements are 
prepayable and the order form 
published in this section should 
be completed and returned 
with remittance. Credit Card 
facilities are available. 



Display — rates per sec (Min. 2scc) 

One insertion : £7,00 

Three insertions : £6.70 

Six insertions : £6,50 

Twelve insertions : £6.00 

Display advertisers should 
preferably reserve space by phone. 



Closing date for Classified 
advertisements is the 10th of the 
month preceding publication 
date. 
Post to 

Your Computer. Classified 
Department, Room H21 1. 
Quadrant House, The Quadrant, 
Sutton, Surrey SM2 5AS, 



firitain's Biggest Selling Home Computer Magazine, 



Viking Software 




New Programs for the 

VIC-20 and CBM64 

from VIKING 

CBM 64 Cassettes 
Stock Control £14.95 

Basic French C5.95 

French Test 1 £7.95 

3D Escape £5.95 

Pontoon £5.95 

OtheHo £4.95 

Draughts £4.95 

VIC 20 Cassettes 
Stock Control* £10.95 

Basic French* £5.95 

French Test r £7.95 

3D Escape £5.95 

Draughts £4.95 

Othello £4.95 

•Requires 8K or 16K Ram Pack 
1st Class delivery & free 
postage. 

Dealer Enquires Welcome. 
Please make cheques/ postal 
orders payable to: 'Viking Soft- 
ware', Unit 3, Meadow View, 
Browston Lane, Browsion, Gt. 
Yarmouth. Norfolk NR31 9DP. 

&3/2 



8BC software Model 8 or 32K Modeta, Mutant 
Attack, Wild West, Earth Defence, Auto 
Dodge, Breakot^i. All five just t3.9& from A. 
Holmes, Fairway House. GKyll Road, 
CrowtKxrough Sussex. 

7/2 
No more cyestrom v/ith your ZX81. Video 
inverter dtsptays sharp white characters on 
^id black background TV screen. A toggle 
switch lets you choose between normal and 
revefse. The snwll PCB fits on top of the logic 
chip inside your ZX81. Kit £4, Built t5, 
includes easy to follow instructions, 
VAT/P&P. Send cheque/PO to: D. Fritsch, 6 
Stanton Road, Thelwall, Warnngton, 
Cheshire, WA4 2H$. 8o)c No. 1 

d/2 




ORICI 

CASSETTE LEADS 
Din to Din & rerrioie 

jack plug 

Din to 2 X 3.5mm jacks 

1 X 2.5mm for remote 

PRICE ONLY £2.50 

Cash with orders includes p&p 

CLARES 

222 Townfiefds Rd, Wirisford. Cheshire 

CWI 4AX. Tel: Wir\stord 51374. 

S8/2 



VIC 20 best and latest Software super new 
ctub with unbeatable offers. Hire a cassette or 
cartridge then if you decide to purchase it 
simply send us the bal4r>oe and we will refurvd 
yoor hire charge or return the cassette en4 H 
d^irc<t hire another. Note no obligation to buy 
whatsoever. Save pounds, join Comcfub 
lodayi Plus a Super Bonus' Ati subscribers 
may purchase a genuine Commodore 16K 
Rampack for €49.96 or an 8K for C29.95. Also 
if you decline this offer, then accept a free 
Comsoft Draughts lUNEX) cassette RRP t6 or 
Comsoft Wotdsearch (8-I6K) cassette RRP 
C8. Send for rr>embership form and free 
catalogue to Comctub, 24 Alton Road, Ayle* 
stone, Lcfcestef, 

42/2 

Sky program for ZX81 and Spectrum 
Computers. Details of Night Sky for every 
night of the year - send C5 to Mf J.S. 
Coombes, 97 Hollyfast Road. Coventry. CV$ 
2AE or send for details of other Astronomical 
Programs. Money back guarantee. 

59/2 



JUPITER ACE 

TENPIN BOWLING 

Fast, skillful game with superb 
sound and authentic scoring. 
Complete with free details of how 
to expand your ace using a 2X81 
Rampack. (Program requires 8K). 
Send £5 cheque plus S.A.E. to: 
K. Longley, 13Sandiway, Heywood 
Lanes OLIO 4BY. 



Acorn Atom 12K, F.P., V*», P.S.U. Plus C30 
wonh Software tt&O ono. 904 9210 Evenings. 

57/2 

Acorn Atom "Space-Man" 2.5K Monsters, 
Power. Phjs, Sound. Highsoore, Auto- Run 
cassene £4 50. instructions S. Brown, 1, 
Ailsa Lane, Itchon, Southampton, 

51/2 



DRAGON 32 




SOFTWARE 




Quatitv software at sensible prices 




Ceterplksr + Space Attack 


£2.95 


Meteor Run + Breakout 


€3.95 


Haunted House 


C3.95 


A'Z Chase + Moneybags 


£3.95 


Forbidden City 


CAM 


Devil's Island 


t4.96 


Golf 


C4.$5 


Goblin Caves 


£4.95 


Prices inchjde p&p. Send cheque/PO for 


first cless return post service Sa.e list. 


APEX TRADING LTD. (Dopt YD), 


115, Creftcont Drive South 




Brighton BN2 SSB 




Tel. Brighton (0273) 36S94 




Acceis/Barclaycard welcome | 




,. 1 



Pools Predict on Spectrum or 2X81 . Score and 
probabifity rating. Rarvdom selector and perm 
calculator. 12 page leaflet and record sheets. 
Simp^ data entry ftom league tabl^ eassene 
etc. C5. Integrated accounts for Spectrunt40K 
program S.A.6. for details, V/iliden Yew Tree 
Lane. Rotherfietd East Sussex. 

13/2 



BUFFER s1iS"p° 

(Near Streatham S.R. Station) 

The best of the mail order items 
available over the counter for 

ZX81 & SPECTRUM 

Open 10.30 to 5.30 Tues to Sats. 

NEW BIGGER SHOP 
NOW OPEN 

Tel. orders using access or visa 
welcome 

210 Streatham High Rd. 

London SW16 

01-769 2887 



Spectrum Programming. Leern Basic Pro- 
gramming the easy way with our fully 
structured ce$$etie course. Let ihe computer 
teach youl 2S0K of programs endirvQ wnih a 
compyierised ettam. Only £9,95, Bafclaycard 
accepted. Sussex Software, Wallsend House, 
Pevensey Bay, Sussex, 

55/2 

VIDEO GAME T SHIRTS Quelfty U.S. 
imported 60/50 poly/ cotton shirts superb 5 
coJour prints based on the arcade games 
PACKMAN ASTEROIDS SPACE INVADERS 
TEMPEST MISSILE COMMAND FR0G6ER 
DONKEY KONG Chest sizes 24"-44" only 
tZM inc P&P. Cheque/P 0. to Neil How. 3 
Vkiofia Road, Leamington Spa, Warks, 

28/2 



MONSTER SOFTWARE CLUB 

Software Ubrary for the 

DRAGON 32 

Top quality cassettes 

FOR HIRE 

AH tapes used with the 

Manuf ectu rer's permission 

SAE for details 

Mofister Software Qufa 

32 Lmmoz Drive. U9MI P«fc 

WifctlMl WMt Ywlis. 56 '2 



WORLD INFO, a database of infocnf^atk>n 
about the modern world. Readers of 
newspapers, students and teachers of Current 
Affairs International I RelatKTns artd Modem 
Studios need it. Includes wars, areas of 
tension, top nr»en, types of regime, alliances 
and much more. 

For ZX81. FuH file on 32K; parts on t6K. Uses 
CampbOlt Systems THE FAST ONE. Spectrum 
version in preparation. £K from WIMSOFT, 
20 Broo^skfe Road, WimtK>rne, Dorset BH21 
2BL. 

19/2 

Acorn Atom 12K + 6S22. Ross Software ROM 
Joysticks 25 Programs 5 Books £230. 0^45 
790324. 

^5/2 




TEXAS 

Tl 99/ 4A 
CASSETTE LEADS 

£7 96 
INCLUDING POST 

AND PACKING 
Single Recorder only 
Orders to: 

Ctares, 222 Towrifields Road, 

Winsford, Cheshire CW7 4AX 

Tel: Winsfofd 51374 

58? 



SPECTRUM SOFTWARE 
AT TRADE PRICES 

FLIQHT SIMULATOR. PILOT YOUft OWN PLANE - VERY REALISTIC COCKRT 

ieK-4SK £2 

HORSE RACING PREPrCTOR. FEED \H YOUR DATA FROM DAILY NEWS- 
PAPER. BY USING THE PREDICTOR AND YOUR INTUITION YOU COULD 
BE ON A WINNER! 16K-4«K £2 

CREEPY LAND. ADVENTURER BEWARE! 16K-48K £2 

GAMES BONANZA. MAZES, INVADERS ETC. 16K-48K £2 

ASSEMBLER. FOR YOU MACHINE CODE BUFFS ieK-48K £2 

MONITOR AND DISASSEMBLER £2 

GRAPHICS AID. GRAPHICS ALL MADE EASY 16K-4SK £2 

ANY 3 £& - BARGAIN. THE LOT £9.50 

CHEQUE/PO * 50p, P&P TO 

T. JEVON, 29 CROP COMMON, HATFIELD 
HERTS ALIO ODG 

64/2 



t66 YOUR COMPUTER, MARCH 1983 




BUTTERCRBFT SOFTiURRE 



14 Western Avenue Riddlesden.Keighley.Yorks. ENGLAND 



our BEST SElltNG ATUO^ONICS fe now avai^bte for 

7X SPBC7RUM ar.d mSSO/VlDiO GBNIE, 

LET BUTTERCftAFT PUT EXCITING SOUNDEFFECTS INTO YOUR PROGRAMMES! 

# YOU design the sounds using your EARS and the 8- function on-scfeen control panel. 

* AUTO- SON fCS turns your sound- designs into progfamme itnes tKat will roproduco 
them exactly — time after time! 

*2S8UILTIN EFFECTS Spaco sourtds . . animtts . . engines . , etc. . . etc. . . u«« them 
just as they come or just twist h berKl h shape them into thousAndft of new effects. 
'EVERY SOUND YOU HEAR can be (nserted into your programmes to bring ihem 
instantty alive — it's nrkagic! Cassene/fnstmctions £4.99 (state machinel. 

PROViPE INTERNAL AND EXTERNAL SOUND ON VIDEO GENIE. 

AMPLIFY YOUR COMPUTER FQR ONLY £4,99 + 50p. p.p.) 

UNlSONtC AMPLlFtER/AM RAOfO. * Use 
cessene lead to conr>ect to your computer 
for instant loud, clear amplification of all 
sound output. 

* UN PLUG and it's a neat pocket radio with 
smart wrist -strap. Needs pne PP3 baneiy. 
(not supplied). 




SURER ARCADE'SYTEL 

GULPMAN 



GAMES FOR ZX SPECTRUM. 
Superb vers/on of shh . . you know wh§tt 
IS rrutics, 9 spe^S. $ gr^es, hirts 
colour/ sound . , fast m/c, hi-score, etc. "An 
extraordinarily good program - well worth 
the pricg." P. C. W. magsiinp. £Sw9S 



WINGED 
AVENGERS 



7 speeds . . laser shm\6 . . mothership re- 
fueling . , smart bombs . . hi-socre , . aH 
m/c . , colour + sour>d, "Or>e of the best 
■SirKtair games yet." /.C. m^g^iirw. ONLY 
£4.S0 



SCRAMBLE 

Condition Red 



Hi-res. coiour-graphics , . missiles , . bombs 
. . fuel dumps . . meteors . , S-diraction 
control , . hi-scofe . . ell m/c. SUPER 
ARCADE ACTION FOR ONLY £4.9® ^f"^ 



Load Lovol Meter with save/load switch for 
the 2X81 or Spectrum. £6.95, Bookham 
54954. 

40/2 

BBC:/MX80FTIII Screen Dump Utility. Extra 
large printout On two sheets or print screen full 
width but down tnstead of acros? sheet. €7. 
Also MZ80K ArfT>oyred Invasion. Gripping 
game« nine skill levels. Sound, good graphics. 
l7. Slavedrive Software, 19 Newtay Lano, 
Bramley, Leeds 13 tS13 2AL. 6/1 

Spectrum software. 'Pools Forecast Aid': 
Results analysit since 19SC? evaKjated trends 
for drawn matches. Direct input and print-out. 
16 or 4dK, bJorhythm: Scitntific life cycles' 
princtplee provide predictbn of physical 
omotionat and intellectual intensity levels. 16K 
£4.95 n6K). £5,95 (48KI to J English, tO 
Meadow Close, Shipdham, Thetford IP25 
7NF. 

15/2 

Informatics student is lookirvg to buy D(- 
Spectrum issue 2. Pieaso contact Mike 
Lucker, Lothringer Str. 103, D-5100, Aachen. 
Tm further interested in program exchange 
with British students. 

37/2 



TRSa) ^ VIDEO GENIE 
SOFTWARE 





ii';;fi*:>jHU 




1 


vSi^^^^^ 




S^-aCC fViiTCS ^ ■ 



We offer a great selection of gan>es and 
utilities from many Eeading software 
houses at reduced prices. As a special 
offer, to introduce you to our software, 
we are giving away, weti almost, a 
software pack with a super variety of 2$ 
lull length programmes on it, and all for 
only £7.50111 Do r>ot miss out? Send for 
your illustrated catalogue today. Please 
enclose an %.ti.t. 

SPARTAN SOFTWARE 

DEPARTMENT YC 

9 CotswokJ Terrace, 

Chipping Norton, Oxon, 
Tetepone:^ 0508 3059, 

31/1 



DRAGON 32 SOFTWARE. Business software 
from £9-95. Educational & games from €2.95 
S.A.E. appreciated. MISTRY MAGIC iyc», 75 
St. Margaret's Road, Bradford BD7 2SY. 

60/1 
VIC20 tape of six games. Minefield, 
Bats/ Bugs. Bncks, Ski-run, Brands, Jeiry- 
Men, Avaitabie from D. Poynter 6 Bonowdale 
Cloee Wtstastow Crewe £5.50. 69/ 1 

Vic 20 f3.5KJ "eomber" Hi Res Adaptation of 
"Bliu" only £1.99. Databram Software 
"Greystoke" Park Road, Bovvdon, 
Aftrincham, Cheshire, WA14 3JG: on 
cassette. 

8/2 



Atom Adventure mvestigate strar>ge happen 
ings in the Old Manor then try to escape. 
12K M/C £6.00 from Fourth Dimension Soft- 
ware. 15 Killearn Drive, Paisley PAl 30G. 

43/2 
VIC-20 (unexparKled) Games Tape: Punkoian, 
Blacfc Knight. Grar>d Prix, Cdvem Shoot 
Amaze, Side Shoot. All 6 for £S inc. 9h9. Fast 
delivery, from: Starraker. 21 Hoyie Road, 
Hoylake. Wirfal. L47 3A6. 

49/2 



SALE 

DRAGON 32 GAMES 


SALE 


STARTREK III Isupefb graphics^ . . . £8.00 

CHECKERS ichildren's delight) £3.50 ' 

3-0 DESIGNER [shapes galore) £5.00 

LUNA LANDER (a challengeh £4.00 

DRAGONSLAYER (the ultimate adventure) 
CI . 


S A.E. Er 50p for Catakigue 
SAINT GEORGE SOFTWARE, Dept 
73 Ling Sueet, Liverpool L7 


. YC. 
29/ 1 



USER-DEFINED GRAPHICS FOR THE 12K 
ATOM + FULL LOWER CASE, Design your 
own niodel characters and move them around 
with m/c speed also screen- editor, keybeep, 
renumber, flashing cursor, auto^repeat, 
extended-line. £4.95. 

SPACE- ADVENTURE f22K) New fast moving 
m/c & Basic program (Atom), Spacecraft 
simiftitors« stunning hi- res graphics £6.95. 
ZX-SPECTRUM (16K) FRUITMAN ail the 
arcade features ghosts, dots, fruit, special 
dots, tunne* arxJ hi score I full colour + 
exciting sound) £4.95 cheques to J. Ouinn 26 
Fofsyth St. ScoKarxJ (PAIS 80T). 

30/2 



WORTHWHILE PROGRAMS 

16K ZX 81 and 48K Spectrum. 

FIRST AID - teaches the principles of 
first aid. Fully scoring. Ages 13+ . 

COMMUNICATOR - Mofse code, 
semaphore, verbal reporting, use of 
telephone. Ideal for cubs and acouts. 
£4.99 each. State machine. Cheques/ POs 
tor 

Network Computer Systems Ltd. 

39 Bampton Road. Luton, Beds. 

9/1 



Acorn Atom 12K + 12K, PSV. £60+ software 
woah £300. Can delivef ANYWHERE Bargain 
£140 061681 287S. 10/2 

Swap your unwanted software via Software 
Exchange Club. S.A.E. for details. UKsec 15 
TunweH Greave SheffioJd S5 9GB. 24/1 

ZX-81 GRAPHICS board £19.96. Fits inside 
case. Define up to 64 characters ( + Inverses). 
SAE, D. Hutchinson (Circuits), t03 Vicarage 
Wood, Harlow. Essex. 14^ 

MZdOK/A Horserace Analysis, Winners 
galore. A sedous program. Cassette: £5.7S. 
Deiails: Paragon Moorside Woodlands 
Wimbome Dorset. 

26/1 
Spectrum Games Sale. Venture (7 games in 
1], was £6. 3 compulsive games, was £5. The 
lot on one cassene for just £6, Bobker. 29 
Chaddenon Drive, Unsvwjnh, Bury, Lanes. 

61/1 



Spectrum 16/48K Software Pack. Contaim 
two space games, two tank games, mini- 
adventure, board game plus more on one 
cassette. £3 to Allan Morton, 16 Ben Ledi 
Road. Kirkcaldy, Fife, , 



BULLDOG 
SOFTWARE LIBRARY 

offer programs for 2X81 /Spectrum, Vic. 
BBC^ Dragon, Oric. These include 
exciting arcade /adventure games and 
educational /business applications. 12 
months membership is £10, hire charges 
£1,35 per two wreek period. You will 
receive an informative monthly news- 
letter, a continually updnttted cutaloguu 
and order (orms. Full money back 
guarantee. Send now; 24 Southernhay 
East , Exeter. Devon. 



Dragon-32 Games for family entertainment. 
Munchers, Breakout, Haiigman, Jackpot. 
Aerof^ne, Lightcycle. All on one cassene. 
Price £6.50 including VAT and PErP. Send 
your cheque to Teesimage Ltd. Bridewell 
Lane, Tenterden. Kent TN30 6EY. 

Acorn Atom 12K ROM 12K RAM P.S.U. 
Books Software £150. Tel; Sheehng 384 
during day. 39/2 



(BHiQ 



Pfogranns for the BBC Micros A a B: Daiek: 
Fast M/C "arcade" game. Hi- res graphics & 
sound. £6, 

Tharon: Dynamic adventure game on an 
Alien Wodd. £4. 

SAE for free catalogue. Cheques to 
Tachyon Computir^, 168 West Wycombe 
Road, High Wycombe, Bucks. HP12 3AE 

21/2 



Spectnim Speaker you just plug speaker into 
the mic. Output. No soWerrng, Volume control 
cased £5.50. 11 Nettleton Close, Canford 
•Heath, Poole. Dorset. BH17 7PL, Mr J, 
Hunter. 

29/2 
Spectrum Races 1-tO players. Bookmaker, 
stunning M.C, (graphics. Pontoon, high- res 
picture cards. Missile destroy tanks, planes, 
before they destroy you. On cassette, £4 
inclusive. Cheques to Rednun, 43 Mere Knots 
Road. Sunderland, SR6 9LG. 

31/2 



DRAGON 32 or 
TANDY TRS-80 Colour 

Lots of programs - fots of useful 
hints and information EVERY single 
month in "RAINBOW" an ©xicting 
new 200-pdge nriagazine from 
U.S.A. 

Send £1.95 (plus large 56p s.a.e.) 
for sample Issue to 

ELKAN ELECTRONICS (Dept. YC). 
FREEPOST. 11 Bury New Road. 
Pfestwich, Manchester M25 $L2 or 
telepone 061-798 7613 (24 hour 
service). 

4/2 



BBC 32K MorK>poly. Up to six ptayers 
including computer. Computer considers deals 
and offers exchanges. Short and standard 
game options. Gamesave facility. I Sketly 31 A 
Hilffield Drhra. Hoswall Merseyside. £6 ifK 
PEtP. 

26/2 
BBC quality programs: Low prices, "Chess 
Clock" {16KI £1.95. "Two-player 

Blackjack" (32K» - £2.45, Datum, 22 
ChescerfiekJ Road, Southport, MerseyskJe. 

11/2 
Sharp M280K, 48K. Year's warranty. Four 
versiorts of Basic, machine code, ch^s, 
adventures, databases, arcade games £325 
02U458 4582. (BlnninghamK 

22/2 
Dragon screencopy programs for Seikosha 
GPIOOA - print both text and hi- resolution 
screens — in up to four ihades — £6.96 for 
cassette pkjs full details - Brain Power 
Penygaer Groes¥wn Cardiff CF4 7UT. 

24/2 



CESIL. BBC model 6. CESi) as described in 
Con>puter Studies - Book 1. Tape pkis 
instructions £8. V. Webb, 3 Poplars Grove, 
Maidenhead, Berks, SL6 8HD. 

41/2 
MZ-60A/K WordPro £8, Databank £6, Copier 
£4, Games £3. List - SAE: DCS. 38 South 
Parade, Bran^haU, Stockpoa. 

52/2 
Spectrum Dtsassembler & Blitz tapes £2.00 
each or £350 together inc p&p. SeiKJ 
cheque/ PO to Holliday, 44 Lennard Road 
London SE20 7LX. 40/1 



SPECTRUM 32K RAM - 
£24.50 

Upgrade your 16K Spectrum to 
48K with our RAM kit Only fits 
Issue 2 machines, identified by 
a large chip in a socket in \\r\e 
with the "9" key, visible 
through the rear expansion 
cutout. The kit consists of 
Chips and instructions, and NO 
soldering is needed. 
£24.50 incL VAT and P€f P 

HAPPY WITH YOUR 
DISPLAY? 

Or have you got problems? 

#Are your whites yellowish? 
#fs ^veri other line a different 

colour (like Venetian blinds)? 
• Do your characters wobble? 

(Some character wobble is 

bound to exist, but it can be 

reduced) 

We have prepared instructions 
to allow any Spectrum to give 
the best possible results, by 
adjusting internal controls. 

Send £1 plus S-A.E. (Sent free 
if you order the RAM. f 

Fountain Computers Ltd., 
DarviH Road, Ropley, 

ALRESFORD, S024 QBE. 

43/ 1 



Vic 20 software Chess £7.00, Panic £7.00, 
Ffogger £9.99, SkramWe £9.99, plus many 
more. Write to: Live Wire 2 Hazel Crescent, 
Thornburv, Bristol {04S41 41283S. 

12/2 

Store information. Storage program for any 
Spectnjm optior\s include: Insert, Dekte, 
Alter, Recall, Save. Only £3.50 on cassette 
with fun instructions. P Banning. Box No. 2. 

26/2 



TINY PASCAL PLUS for PET n6K + , all 
ROMS, disc Of cassette* and APPLE 
tdtscl. Package consists of km editor, 
compiler, p-code interpreter, 60 page 
manual h sample programs. £29.^5 

VIGU imeraciive ^mm language f 0* PET 
or VIC i63K + ). Includes 9 games & 
50/70 page manual. £19.95. 

SAE for fiib software catalogue to: — 
ADAMSOFT (dept, YC», 18 Norwich 
Avenue, Rochdale, lanes. 0L11 5J2. 

20/1 



Software urgently required If Arcade games. 
Can you write programs for Vtc 20, ZXS1, 
ZXSpectrum? We pay top prices for good, 
exciting ganrtes. Put your genius to wodt 
with high rewards. Write to Northwish, 
Balli Building, Stanley Street. Manchester 
M35FD or phone 061 &32d14 today. 

23/2 



Weekend courses in Sinclair Basic, starting February 

1983, 15 hours of instruction from a qualified lecturer, 

Friday evening to Sunday evening. 

Luxurious 3-star Worcestershire Hotel, all roonns with 

bath and other facilities. 

£55.00 inclusive. 

GAINSBOROUGH HOUSE HOTEL 
Bewdley Hill, Kidderminster 

(0562) 754041 y^ 



YOUR COMPUTER, fVlARCH 1983 167 



BBC (32K) and ViC 20 (6.&Kf 



DON'T JUST TALK ABOUT 
EDUCATIONAL SOFTWARE ... TRY 
0URS1 EVERY PROGRAM IS 
CLASSROOM-TESTED AND FULLY 
GUARANTEED. 

"LETTERS' (88C only) - for 350*4106 
- loachos tbo correct way to form lower- 
case l«nef% 0I the atphabet. Great 
graphics. Grve your child a hed<j start in 
Feaming to write, £9.96 for suite of 5 
programs. 

"SEQUENCES" Seven common 
mathematical soQuences clearly 
demon&tfated using full coiour and sound 
(09 primes, squares, Fibor^acct . . .} £5.95 
"METRICS" Revises and tests 
understanding of volume, length 
cdpaciry, area, and maw. Ptve programs 
on one cap« for £9.93. 
. . . and many more. SAE f c complete list 
I o : 



Chalkscfi Lowmoof Cottage (YC3). 

Tonedale. Wellington. 
Somerset TA21 OAL. 062 347.?n7 

16/2 



Spectrum ASK apecial introductory offor. 
free diary syitem with the Sank Account 
System, written to protessron^l standards, ful 
screen entry, maintams transaction file 0I 
St^ndir>g Orders, Salary, Cheques, etc., prints 
stotements^ why wait for the Bonk, cassette 
am! user manual, £5,<X), Kim Gouklstone. 4f 
6u«le*gh Avenue, Waltington, Surrey. SM€ 
7JG. 32/; 



MUSICSOFT 

BBCMtCR0 32K A/B, 

5 music ganws of memory and dexterity. 
Multicolour graphics. Fun tor 5 year ofds 
yet 'nistratrng for graduates. Variable 
sptHj<ts and scale levels. Cassette and 
ln$tnjciior*s £3.50 

Cheques to Musicsoft 
12 FaUowfteld Ampthil. Beds. 



16K ZX8I Load5 t manuals ASM1C chip for 
m/c progfammir>g, £60 wortn of games -*- 
mags, tape recotder ail for £ 120. Good Easter 
322. 

5/2 
Vic 20 owners. Exciting educatonat programs. 
Suriabic for children aged 6-12 years. £5.00 
pbs 50p P&P, Send for details E,C.P. 99 High 
Strwei, hail Wesion, St. Noots, Cambs. 

e/2 

mm 



Primers for £14.957 Yes, onty £14.95 for a New 
plain paper printer. Cheques/ P.O. + £1.25 
P&P to: - P. Ralpha, T Duxford Walk. Moston 
M/106JN. 

34/2 

ZX6I/16K Games Cassene* Four Prograrm 
{One Armed Bandit, Word Game, Lunar 
Landing, Golf). Alt on one tape. £4.95 to 
Ushers, 60 Station Road, March, Cambs. 

54/2 

TEXAS Tt99/4A SOFTWARE on tape, from 
£1.95- Send s.a.e. for list. Apex Trsdir>g Lid. 
(YT), 115 Crescent Drive South, Brighton, 
BN2 6SB. 

^/2 

ZX81, 16K Tuition, testing, problams 
(randomised) on Pythagoras Thewm - fo* 
C.S.£./'0' mathennatics. Previous knowledge 
unessential. Casscne £4.50. C- Jones, 4 The 
Eyrie, Burton- on Trent DE15 OOT. 

3/2 



SPECTRUM 

INTRODUCTORY OFFER: Large 
selection of software ar*d add-ons at 
discount prices tnc1udir>g: 
Masusrfiie £14.25 
The Hobbft £14.20 
Pimania £9.50 
Black Crystal £7.12 

Time Gate/Football Manager/ 
Penetrator £6.60 

Ofbiter/Ground Attack/Gulp* 

man /Nightf rite £5.66 
Escape/ 30 Tunnel /Maieman £4.70 
Ov«r 75 different programs in stock t 
PBP sop Free on 3 ^^ tapes. 
SerMJ large S.A.E. for complete list. 
IVYSOFT, Oept YC, 
9! Cleeve Drive, lyybridge. 
Devon PL21 9BS. 
Tet: (07564) 4088 

63/2 



ZX61 and Spectrum educattonal and gamm 
software seid SAE. 8 HorsfieW 23 Lealholm 
Croscent Middlesrough. 

27/2 
Computer or Daisy Wheet Printer v/anted 
yrgenity. anythir>g considefcd. 6SG, 24 
Southernhay East Exete/ 0626 862455. 

33/2 
VIC-20 Software Cassettes, £3.95 each inc. 
postage. No. 1: The Raider, Spacewarp. 
Breakout. No. 2: Skier, Cowboy shoot-out. 
No. 3; Scramble. All for the unexpended 
VIC-20, uses Hi Ros cok>ur graphics and 
sound. Cheques/ P. O.S. to A. Carter, Ewelme, 
Ewen, Cirerkcestof, Gk>s. GL7 68 U. 

38^2 



BAUG SOFTWARE 

Introductory offer ATARI 
7%% off hardware up to 20% 
off Software. Commodore and 
Drag on. 10% off X87 key- 
board £26,00. 

Telephone 0232-621221 for 
details P.O. Box 123, Belfast 
BT10 ODB. 



3p<K:irym software library. Weekly hire from 
50p. Try programme out before you buy. Send 
stamp for free caiaiogue to Thomas 
McOueen. 25 Blenheim Gdns; Brixton Hifl, 
London. S.W.2. 

50/1 



DRAGON 32 

Five Exciting Games for 
ONLY £5.40 

Hi-re* colour and graphics 
fun for all the family 

BULLS a cows 

MAZE RUMNER 

HAMURABI 

RATTRAP 

EARTH DEfENCE 

ARGENT SOFTWARE LTD 

Dept VC 

MJdcourt House 

25 Lynwood Chase^ Brack nelL 

Berks RG12 2JT 4^/2 



DRAGON 32 AND SHARP MZ80K 
SOFTWARE 

Games Packs - £6.50 each. 

Gamos Pack 1 — Bovyfing, UFO, Muncher, 

Micropoty. Mastermind. 

Gam^s Pack 2 — Race-chase. Dapth 

Chatg*. Motor Cross, Glorious 12th, 

Canyon Bomber. 

Games Pack 3 - Tank Battle. Reaction 

Time. Blind Ma?e. One Man ar»d Hg Dog, 

Life. 

Game Pack 4 - Poker, Pontoon. Roulette. 

Otheto, Stock Broker. 

(Sharp only) 

Adventure Games 

Devils Triangle - Sail to Bermuda but 

beware of the Bermuda Triangtel - £5.00. 

Earth Rescue - Search the Galaxy for a rare 

mineral needed for Earths survival - C5,00. 

King ol the Valley - Try to control a 

kir>ecom and its people - E3.00. 

Desert Patrol — Find your way across a 

desert but beware of its inhibitants! — 

f4.00. 

Bdacatiofmi 

Maths Tutor — A set of programmes 

designed to leach maths to chikJren from 

310 vrs. - £5.00, 

Word Qu« - Frrwl the Ndden words in a 

jumble of tetters - £3.00. 

SotkJ cheque/ PO or SAE for details to 

Abacus Software 
20 Rhosteigh Ave. 

Sharplea Park 
Bolton BL1 6PP. 



Atom Acorn futty expanded never used game 
cassette. Only £120. Phone ^1 6^0 after 5. 

2A2 



DRAQON32 
AND BBC MODEL 8 
747 FLIGHT SIMULATOR 

Swp«rt)4y rff«lsic^ imtf un^cncjccyv b^C (HV>«i 
wiMv in I^Rm or4pf)K«v Mttt* ikmMoon 

•nd hfOmMe J^mm, Thm 32X progrwn 
vam th« Oftgon'i Mwet/Umnt |}r*priiei 
hc iii fn tp tfM M to pfoduc« m* tpcm 
i l lfc l tfc ■W w f WH aiptev Vft l*tn on a 
hBunmeempum. Th«#«f«2l mt<§ah*r>i 
«f^ 30 <<h» intfctof* it*« dt»grmtM. V^ 
confOi If fUloi, wiraftf. cwrtitofs. 4w^tor 
trirrv fU««. itMK t p oi tri, Un^n^ gmr. 

lixJva*t opn«oi iQ tun wM) tiM-^ <x 

CH«*n» C9^ IfP «r^ VAT Mdudvdl 
O A,C.C LTD.. 33 W«vw1«y ltd , 
Hmm^. Qtr. MtrKhMtvr WHZ JBH. 



KD rrm 




OOOOO 
aaaa 

0000 
GGGQ 
QQQQ 
O00O 




CLASSIFIED 



ORDER FORM 



Classified Rates 

Lmog©: 30p per word |Min 15 words) — 
prepoyoble 


Please insefl the following advertisement in Your Computer Classified Section 




Ltoag& adv^fttsers shookf compfetc (he form 
provided in SLOCK CAPITAL S. Phone number 












LINAGE 




counts as 2 words Nam^ mdsddress to be 
pafd for tf used m advents^rmni Bom Nym^r 
rf required ts £3 00 enrra 

Display - roles per sec (Mtn 2^CCJ 
One Insertion £7.00 
Three Insertions id.70 
Six Insertions £6,50 
























£4.50 














£6.00 




Kvelvetrtsertfons £6.00 
Oisptay adventsers shoufd provfde sepsf9te 












£7.50 




copy and preferabty reserve space t>y phone 
(01^661 303 U 












£9.00 




Method of Payment 

Cheques etc, should be nnode poyoble 












£10.50 




fo \?C Business Press Limired ond 
crossed "& Co* 1 enclose herewiih 












£12.00 




chequej'PO foe 
£ 












£13.50 




P loose debit my Access/Viso Borctay 
Card/Amef icon Express.Diners Club Inl^ 
^os below 






-1 






£15.00 






No. of insertions required |~] Box No. required YES/NO 



HMAl (Ptease include initietsh 
ADD(?f SS , 



SIGNATURE 



^OSttO: 

Cut OuT the order form arnJ return 
together vvith your rennfttBnco to: 
Classified Department, Yoyf Computaf, 
Room H2n, Quadrant Hou$e, The 
Ouadrant, SuUon, Surrey SM2 5AS. 
(01) 661 303t 



Payment by credit cord please stote address card is registered 
Daytimetel.no ,.,...... ................... 



THiS FORIVl SHOULD BE RETURNED BY FEB. 28 FOR APRIL ISSUE PUBLICATION 



1 68 YOUR COMPUTER, MARCH 1 983 




At last! The thing Jupiter Ace owners have waited patiently for. 

A minimum of 16K RAIVI plus the added benefit of extending to 32K by a simple plug-in 

module! 

Now you can start to program seriously in FORTH without the restriction of 3K RAM. 

Make no mistake. Not only is the PACER the first RAM pack for the Jupiter Ace, it is a totally 

professional piece of equipment. 

Look at just some of the features:— 

* 16K RAM expandable to 32K * Professionally cased to enhance the look of your computer 

* LED Power-on Indicator * wobble free connection — no loss of programs! * A fully tested 
product * Complete with 1 year's full warranty. 

The NEW 'PACER" is available now direct from STONECHIP ELECTRONICS. / m«|«» 
Write now for quick delivery by mail. ^^■■■If 

Remember: For more power from faster FORTH . . . you need a PACER! ' ^ — — «^ 



POST TODAY to STONECHIP ELEaRONlCS, 
unit 9, The Brook industrial Estate, Deadbrook 
Lane, Aidershot, Hants. (Telephone: 0252 318260) 

Please forward me the following:— 

"PACER" RAM packs for the Jupiter Ace @ 

£29 95 
i6K'expansion modules (to expand "PACER" 

to 32K) @ £19.95. 

I enclose full remittance of £ made 

payable to Stonechip Ltd. 

Please note: All prices Include VAT, Post & Packing 

for U.K. deliveries (overseas add 15%) 



-[£29^5 

Name: °^^^^!^^^^ ' 



Address: 



STONECHIP 
ELECTRONICS 

"More ways to make more of your computer" 

Delivery approx 14 days 



YOUR COMPUTER. MARCH 1983 169 



DRAGON OWNERS . . 

HAVE WE GOT A GAME FOR YOUR 

WINTERSOFT PRESENT 5 GREAT CASSETTES TO TEST OUR METTLE 

AGAINST THE DEADLIEST ADVERSARIES, KEEP YOU GUESSING, 

AND STRETCH YOUR CREATIVITY TO THE LIMITS. 



WtKTI«^0<T 




THE RING OF DARKNESS 

"he first fully hl-r*»s graphic adventure game for 
xhe Dragon 32. Be you warrior. wt;ard. Of thief 
vou travel the ervchsnted land, trade with fools 
ar>d kings alfkc, dare iHe depths ol vast, raonster 
filted 3D dungnon^ and face, at ta$t th<» 3«crot 
quest. If vou strvive. It irvciudes a savo game 
facilfty in could tdke you weeks to play). 

tTD.0O 




DRAGON TREK 

An advanced Star Trek game in ht-res cok>ur. 
Mixed text and graphics, movirtg Kftngons, 5 skBI 
levels, onboard computer arrd lag time 
interaction will have vov zapping Ktingons till 
starda!e2477. £6.99 



fe '3 



PEPPER'S GAME PACK 
6 GREAT GAMES ON ONE CASSETTE 



MASTBRBRA/N 

You'll need all your wits to crack the computer's code. 3 levels 

of difficulty. 

PEPPER'S BREAKOUT 

Knock the bricks from the wall. Operates by joystick or 

keyboard. 7 Skill levels. 

TERRIFIC VALUE - ALL SIX JUST C7.% 



NAD THE NECROMANCER 

Nad has stolen your book of spells. Track him through the 
catacombs and use cunning to trap him, but watch out for 
serpents, trolls, ghosts, etc. 

MUSHROOM MUNCHER 

Stem the epedemic of blue mushrooms and flying pods. Look 

out for the munch monster. 6 skill levels. 

CHESSBOARD TRACKER 

Use cunning and strategy to trap the computer controlled 

runner, but beware deadly blockouts many skill levels, 

CHAMELEON RUN 

The canyon walls are closing in, can you fly the shuttle to level 

10. 5 skills. 

Available from selected dealers or send cheques/ POs made payable to: 

S.W. WINTER a- CO. LTD. 

101 Westminster Bridge Rd, London SE1. Tel: 01-928 5945 01-633 9611 

We have Dragon 32's in stock NOW £173.00 + VAT 



ARTIST'S DESIGNER 

Produce intricate designs io hi*fes graphics and save ihem on cassaue. Full list of 
features include joystick or keyboard control, circles, paint, shape replication and 
text merge tabetl^ng. Ideal for education, diagrams, home video captions. £6.99 

THE MINSTREL 

A graphic music Sheet on the screen aJlows you to compose masterpieces, and save 

them on cassette . Educational an6 entertaining. £5,99 



1 







ADVERTISEMENT INDEX 






• 


A 




Da vin Soft 


82 


Level 9 


110 


Remsoft 


158 


Active Software 


105 


Dams Business 


27 


Llamasoft 


6 


Richard Shepherd 


48 


AF Software 


62 


Downsway 


99 






Ross Software 


159 


AGF Hardware 


142 


Dymond 


159 


M 




S 




Abacus Electronics 


143 






MC Lothlorian 


104 


Silvasoft 


49 


Acornsoft 


24/25 


E 




M Gear Engineering 


144 


SW Winter 


170 


Acs Software 


114 


Educare 


110 


Malva Ltd 


154 


Salamander 


141 


Amba 


145 


Eltec Computer 


105 


MapJin Electronics Supplied 12 


, 13, 147 


Severn Software 


104 


Amersbam Software 


138 


Epson 


130 


Melbourne House 


34,56 


Shards Software 


79 


Anirog 


16 






Men>otech 


8,9 


Silca Shop 


7 


Arttc Computer 


156 


F 




Micro Aids 


19 


Simon Hessei 


164 


Audio Connputing 


inside back cover 


Foil Kade 


146 


Micro Game Simulation 


82 


Simon Software 


160 


Auto Ram 


95 


Fuller Micro 


35 


Micro Mania 


82 


Sinclair Research 117, 


118. 119,120 


Automata 


141 






Micro Ware Leicester 


94 


Sir Computers 


147 











Midland Computer Fair 


158 


Softex 


155 


B 




GCC Electfonics 


144 


Movie Drome 


95 


Software Farm 


108, 141, 164 


Bibi Magnetics 


164 


Gemini Marketing 


1^, 163 


MST 


79 


Software For AH 


5 


Basic Care 


76 


Gemini Software 


160 


Micro Management 


42,43 


Software Library 


146 


Bee Bug 


145 


Gitsoft 


142 






Software Supermarket 


80 


BiPak 


128 






N 




Stone Chip 


4. 83, 169 


Bridge Soft Ware 


t 147 


H 




National 2X80 Club 


17 


Stork Rose 


63 


Bug Bear 


144 


Harris Lockyer 


140 


New Genef ation 


157 


Sunshine Publishing 


58 


Bug Byte 


126,127 


Hewson Consultants 


10, 11 


Next Computes 


154 


Superior Software 


106 






Hisoft 


138 


Northwish Inskl© Front Cover 


Swantey Electronics 


132 







Hunter Electronics 


157 










CJE Micro 


102 


H & H Software 


143 


O 




T 




CP Software 


134 






Oakleaf 


140 


Ttmedata 


142 


Clares of Winsford 


159 


I 




Oric Products 


46,47 


Transform 


114 


Calpac Software 


160 


Imagine 150.151,152, 


153. Back Cover 


Oxford Publishing 


95 


Trojan Computers 


159 


Cambridge Micro 


96 


UK Software 


161 


Oz Software 


157 


Twickenham Computer Centre 146 1 


Cambridge Research 


112 


Impact Software 


132 










Campbell Systems 


125 


Iniertext 


158 


P 




V 




Camel Software 


128 


Interceptor 


108 


Pase Computers 


114 


Vic Polyphonic 


82 


Cascade 


112 






Phipps Associates 


74 


V €t H Computer Service 


140 


Cheetah Marketing 


116 


J 




Picturesque/ Addictive Games 


99 


Victa Ceramics 


157 


Chromasonic 


165 


JKGreye 


102 


Print and Plotter 


72 


Video Software 


160 


Comnrw>dofe 


22/23 


J RS Software 


104 


Pro Software 


125 


Visionstore 


18 


Comprosys 


73 






Program Power 


36 






Computer Concepts 


106 


K 




PSS 


66 


W 




Computers for Ail 


14/15 


Kempston Micro 


110.154 






Warp Factor 


125 


Computopia 


143 


Keyword 


79 


Q 




Workforce 


92 


Control Technology 


26 






QEO Systems 


158 


Wiffiam Stuart 


95 


Crystal Computing 


145 


L 




Quark Data 


61 


Watson Software 


132 






Laserbug 


138 


Quick Silva 


52, 102 






D 




Learned Information 


32 






X 




DJL Software 


128 


Leisure Mail 


79 


R 




Xavrersme 


140 


OKTronics 


67, 86, 87 


Leon Noel 


144 


Redditch 


89 







170 YOUR COMPUTER. MARCH 1983 



THE INTEGRAL EXPANSION 
SYSTEM FOR VIC 20 




THE 
SRC 16 
The first 

cartridge 
consider for 

VIC 20 

• It's a direct replacement for the Commodore 16K RAM cartridge but it's no ordinary cartridge 

• It has space for the 40 column ROM or a programmer's toolkit ROM 

• It has space for a cartridge slot, accepting any Commodore cartridge 

• It has space for an extra 16K bytes of RAM, making a total of 37iK (28159 bytes free for basic, 8192 bytes for machine code or 
game simulation) 

• It's part of a complete system including motherboard, Eprom programmer, 16 bit second processor, etc, and is available at many 
computer stores and in most European countries 

• It's designed, manufactured and fully guaranteed for 6 months by: 



STL 



SOLIDISK TECHNOLOiGY LIMITED 



COMPUTERS PERIPHERALS MICROPROCESSOR DEDICATED SYSTEMS 
-,T<lr(0702) 6mi44/6 13081 Trade Name: AUDIO COMPUTERS 

87 Bournemouth Park Road Southend on- Sea Essejt SS2 5JJ England 



wsmm- 



■'I*- 






w^^^: 



IF YOUVE ALREADY GOT A SINCLAIR RAM PACK, 
ALL IS NOT LOST! _.. . .■„.,».. , — A 



The Fix-A-Ram offer is for yoiL 



£0.50 



IKMt And ;ur4»9 



A' 



Z\ 



Program crashes on the ZX81 are only too well known, but one of the most 

common reasons is 'wobbling*. 

The Sinclair Ram Pack is attached to the computer by a snnall contact area, as 

shown in figure 1. 

We have designed what is much needed: a plastic sleeve, which is sandwiched 

discreetly between the Ram Pack and the computer, called the FlX-A-RAM (see 

fig. 2). 

RESULT: a perfect match and stabiliti;. 



Fig. 1 



IF YOU'RE LOOKING FOR A 16K RAM PACK, 




The 
Special 
Ram pack 
is for you! 



• It's a direct replacement for the Sinclair Ram Pack, but it's no ordinary Ram Pack! 

• It has space for a ROM. cither for games or more serious applications such as electronic^ 
spreadsheet etc. ... 

• It has space for the X ROM CARD 

• It has space for a keyboard sounder 

• It doesn't wobble! 
Available from Solidisk Technology Ltd. at the above address. 















Imagine Software, Masons Buildings, Exchange Street East, Liverpool, Merseyside L2 3PN. Telephone: 051 -236 0407